Disclaimer – Everything either does belong to Joss or it should. I’m just borrowing his shiny ‘verse for a while.

The 21st Lancers belong to the British Army so I’m borrowing them too. I hope they don’t mind.

Thanks to my regular readers for making it worthwhile to continue the story and special thanks to my Proof-Reader Landry

* * *

Transport Ship Serenity – Preparing to Enter Atmosphere – 2520AD

Zoe unhitched the ropes that had been securing the steel crate to the deck and hooked it up to the winch.

Mal had already taken the bay controls and pressed the button that opened the bay’s secondary cargo lock, the two internal doors opening inwards revealing the small space between the external hatch and the bay itself. He activated the winch and lifted the crate with Zoe steering it into position.

‘Lower away.,’ she said once it was properly positioned.

The winch slowly lowered the six foot long steel crate into the space between the two locks. ‘You’d think they’d built her for this,’ Mal said, ‘just like a proper bomb bay.’

‘Rather not have to do it again though, Sir.’ Zoe replied and unhooked the winch once it was in place. As Mal wound the cable back in she reached down and grabbed a piece of string with a clip on the end and snapped it to a small hook.

‘We’ll arm it after we make transition,’ Mal said. ‘Wouldn’t want the shaking setting her off.’

‘For the record, Sir, I’ll feel a lot more secure after we get rid of it. These things give me the creeps. Give me a nice grenade any day,’

Mal grinned. ‘You know if you’re standing next to the thing it don’t really matter if it’s a grenade or an H-Bomb. You can only get so dead.’

‘Principle of the thing,’ Zoe responded. ‘Really think this’ll work, Sir?’

‘It had darn well better. Those things aren’t cheap,’ Mal responded.

Zoe picked up a sack and began pouring the contents into the small space with the bomb. ‘It took me and River gorram hours to cut up all this stuff now we’re just dumping it.’

Mal grabbed another sack and started pouring. ‘Better not to risk them shooting the thing. It might get damaged and not go off.’

‘I’d be more worried if they hit it and it did go off before we got out of the way, Sir.’ She finished emptying the sack and threw it to one side.

Mal did likewise and then leaned down to flick a switch that was spot-welded to the crate. ‘Electronics are on. I’ll arm it by remote once we’re in atmo.’

His second in command stepped over and took the control. ‘Closing bay,’ she said.

The two powered doors closed again. They sealed shut with an audible thump.

‘Guess we’re well and truly committed now because I ain’t hauling that thing back out of there,’ Zoe stated.

‘We’ve been committed for weeks. Reality is just catching up with intention,’ Mal replied.

Wash’s voice boomed out from the intercom. ‘Brace for transition.’

Zoe and Mal grabbed hold of something before the wave of mild nausea hit them. It was like this every time they entered a decent gravity field. The ships gravity engine sought to counter the field they were entering and the feeling was fairly unpleasant if short lived. You got used to it but you never got to like it.

The feeling passed, then the ship started to shake, very slightly at first but building fast.

‘This de-orbit’s going to be a bit rougher than I’d like but I figure we want to get in and out fast.’ Wash announced into the intercom as he piloted the Firefly through the transition from the black into atmo. The ship was now starting to shake pretty violently thanks to both the high speed and the angle of entry but Wash had made far worse re-entries and although his face was a mask of concentration rather than the usual half-grin he wasn’t worried, at least not about the flying. He was just being professional.

Wash took his job seriously. He liked flying, heck he’d pay to fly if their weren’t people silly enough to pay him to do it but he always made sure to keep at the forefront of his mind that it wasn’t just the control column in his hands but the lives of everyone on the ship. Life was generally a joke to Wash but piloting was a serious business.

‘Three minutes to bomb-run,’ he said into the microphone, his words echoing from every internal speaker on the ship.

No the flying wasn’t worrying him but the bombing sure as hell was.

Wash pulled on a set of night-vision goggles and turned off the lights on the bridge. River had another pair and after struggling with her long hair put hers on too. Through the goggles the pair could now see the ground below. They were flying over a small mountain range giving way to rolling hills before the Reaver encampment on the coast.

The pilot felt beads of sweat beginning to form on his forehead. He wanted to wipe them clear but for some reason he couldn’t bring himself to take his hands off the stick again the reality of the situation had overtaken him.

An arm leaned just into his field of view and wiped his forehead with a sleeve. ‘Is that better?’ River asked. Whilst Mal and Zoe were in the bay she was still on the bridge to help with the countdown whilst Wash got on with flying.

‘Yes, thanks,’ Wash said gratefully.

‘I never expected to ever be doing this sort of thing either,’ River said. ‘It’s exciting though,’

Wash flicked his eyes over the console. An extremely ill-defined dim blob on the radar indicated Shadow was about to arrive.

The pilot steered the old civilian transport into an attack run.

Down below his wife was helping her old army buddy get an atomic bomb ready to drop on the biggest mass of Reavers ever assembled in the known ‘Verse.

‘Wacky fun,’ he mumbled through clenched teeth.

* * *

Shadow produced a very small radar echo. Serenity didn’t.

As soon as the Firefly entered atmosphere half a dozen Reaver ships which had been unable to get a lock on the sleek warship immediately found themselves with a clear shot at something. They didn’t know what it was but it wasn’t one of theirs and it was something they could hit at last.

A dozen anti-ship missiles boosted more or less simultaneously and hurtled up to meet the incoming transport. Serenity didn’t have much in the way of threat recognition software but it knew when it was being targeted by a whole heap of missiles and the console started to beep furiously, rapidly rising in pitch as the missiles closed.

‘SHADOW!’ Wash yelled. ‘I’VE GOT INCOMING!’

A black shape tore across the front of Serenity from below did an incredibly tight loop and finished the manoeuvre flying alongside to starboard.

‘I am well aware of that,’ the AI radioed back and Wash watched as a storm of Laser and Particle beam fire arced out from the warship. The beeping stopped almost simultaneously. ‘Get a grip, Pilot,’ the AI signalled again in a clearly mocking tone.

The missiles weren’t the only thing getting a lock because a bright light washed across the Firefly’s bridge.

‘Laser hit. I’m dead,’ thought the pilot, when the light disappeared as fast as it had arrived.

Wash blinked a few times and saw past the spots in his vision that the AI had moved forward to intersect the beam shielding the Firefly. It was also firing back and the incoming beam stopped abruptly. The AI was flying with nose raised high using the canards and vectored thrust to maintain the high angle of attack needed to shield the Firefly. It meant a great amount of wind resistance to struggle against but its engines were more than adequate to compensate.

‘You have sustained minimal surface damage,’ the AI reported looking the other ship over via one of his optical sensors. ‘The beam was pretty weak, and from the wattage and spectrum I estimate it was only a jury-rigged mining laser. I’ll stay between you and any more incoming fire.’

His vision began to clear. ‘Are you certain? I don’t want to go back up and only find I’m holed when all the air rushes out,’ Wash asked.

‘The point of impact shows no burn-through.’ Shadow confirmed. ‘The hull is slightly pitted though and the paint job is in even worse shape than the rest of that bucket.’

‘We’re getting close and I can’t take laser hits like you can,’ Wash told the machine.

River was sitting in the other chair. Other beams seemed to be reaching out for the Firefly but the warship was taking the hits instead. It was smaller than the transport but by staying a reasonable distance ahead it covered a wide enough section of firing arc to shield the larger vessel.

‘Shadow how much of that can you take?’ River asked.

‘If bits start coming off you’ll know it was too much,’ the machine replied sardonically.

Shadow was struck by another beam. He returned fire but no sooner had that one been neutralised than two more took its place the closer to target the more systems would be able to get a lock.

One advantage the machine did have was that although the beams were all striking along his underside one of the outer layers of his hull was a heat superconductor which transferred much of the incoming thermal energy away spreading it across a much wider area of his hull. It wasn’t a perfect defence but it would allow the ship to withstand a large amount of incoming fire before his hull was burned through.

There were patches of inferior material in places but most of these were not in the field of fire and when those that weren’t were struck the AI was shifting position slightly before burn through occurred.

He was still getting hot though.

Wash watched the AI ship ahead and switched his goggles from light amplification to infrared for a moment. ‘Qù tāmāde,’ he swore ‘You could fry an egg on his hull.’

River shook her head. ‘Probably too hot to do that properly,’ she commented. ‘You could probably melt lead on his hull though.’

Wash checked the console and turned on the intercom again. ‘One minute to target,’ he said loudly. ‘I repeat, one minute to target.’

* * *

Down in the bay Mal hit the intercom. ‘Advise again at thirty. Give me a countdown from ten,’ he ordered. ‘River, you do that. Let Wash fly the boat.’

‘Yes, Captain,’ he heard the girl’s voice answer via the speakers.

Mal pulled the bomb’s remote trigger from his pocket and flicked the final arming switch. Inside the cramped cargo lock below the bomb went completely live.

Zoe reached over to take the hatch controls. Mal shook his head. ‘I’ll be doing that,’ he said. ‘My responsibility,’ he stated.

‘This feels different,’ Zoe said. ‘Not like a gunfight at all. Not as real somehow.’

Mal nodded. ‘Sure as hell feels different alright,’ he agreed. ‘Find something to hold onto. The last few seconds are going to be a steep dive.’

Zoe moved so she could hold onto a railing taking it in a vice-like grip. Mal was doing likewise with the remote back in his pocket and the bay controls in his free hand.

River’s voice boomed out again. ‘Thirty Seconds.’

* * *

‘Shadow, I’m about to dive to target,’ Wash told the AI.

The machine replied. ‘I’ll stay ahead for most of the dive but for God’s sake tell me before you’re dropping the bomb because I don’t want it dropping into my engine wake.’

‘Will do, Shadow,’ Wash responded. ‘Diving in ten, nine, eight, seven…’ the pilot was surprised his voice sounded so calm. ‘… two, one.’

The Firefly went into a fairly steep dive right over the Reaver encampment. They were several miles up but moving at a speed that would get them closer to the ground very quickly.

Lacking any kind of guided delivery, but still wanting to drop the thing from a good distance away the crew had resurrected the easiest method of accurate bombing dive on the target so when you drop the bomb its momentum keeps it going the right way at least until the parachute opens at about five thousand feet. It would drift from there but it wasn’t windy and what they were dropping didn’t really need to get exactly on target to get the job done.

River flicked on the intercom again. ‘Drop payload in ten, nine, eight…’

* * *

The Captain gripped the control as Rivers voice continued to count down. ‘…four, three, two, one, DROP!’

Mal pressed the button.

Underneath the Firefly the external bottom lock opened. As soon as it opened a fraction thousands of strips of aluminum began to fall out and were scattered like confetti.

Shadow had already cleared out of the way, pulling up slightly, and recorded the event for posterity.

The lock slid open quickly and as soon as it was able to fit through the gap, a six foot long steel crate fell out of the bottom of the old Firefly transport completely surrounded in a cloud of pieces of silver foil.

‘TIME TO GO WASH!’ Mal hollered at the top of his lungs as he pressed the button to re-close the hatch.

The package had fallen perhaps thirty feet before the piece of string that still connected it to the ship pulled taut and pulled the ripcord of the parachute attached to it. The crate was going at a hell of a velocity after the dive and continued another few hundred feet before the parachute opened enough to slow its descent.

* * *

Wash pulled back on the column and slammed the engines to maximum power. The Firefly pulled up from its dive with surprising agility almost as if it knew what had just been done.

Behind the ship an immense cloud of aluminum foil had been left behind. It was another old military technique dating back to the Second World War on Earth-That-Was. The British Royal Air Force of the day had codenamed it “Window”. Later it came to be called chaff.

The cloud of aluminum foil strips sent Radio Direction and Ranging absolutely crazy. At least it did to the sort of archaic and civilian radar gear the Reavers were still using. The huge cloud showed up as a solid mass, overwhelming the Radar systems which simply couldn’t discriminate between the foil and the real targets.

Shielded from being tracked from below, Serenity and Shadow hurtled skywards at maximum power.

Also lost in the blizzard of radar jamming foil was a big steel box dangling on a parachute.

* * *

Far below Serenity a Reaver looked upwards with binoculars. He was wearing a headset which was telling him that the attacking craft seemed to be fleeing and had dumped chaff to cover their retreat. Some voices were clearly celebrating that they had driven off the enemy.

Some of the more disciplined were still on the look out though. One of those ships was stealthy and the “retreat” could be a ruse. He scanned the skies just in case.

Hang-on what the hell was that?

He zoomed in with the powered binoculars. No, he still couldn’t get a decent view. There was something falling but it was too dark to see properly. Looked a bit like a parachute. Maybe they’d shot one of the attackers down?

Was that a person dangling from the parachute?

Gorramit why did it have to be nighttime? The Reaver wished it was a bit brighter.

Then it was.

* * *

Transport Ship Granite Gorge – Oort Cloud – 2520AD

Simon smiled. ‘Alright at the request of certain crew members I am changing today’s science lesson from biology to physics, nuclear physics.’ He paused. ‘Well, to be specific how an atomic bomb works.’

Cally grinned broadly. She knew if she badgered him enough he’d fold. Jayne was hovering pretending not to be interested but anything to do with weaponry attracted his attention.

The Doctor had set up a crate with a sheet of plastic stretched over it to act as a blackboard and was drawing upon it.

‘If you’d remember our previous lessons on atoms each element has a nucleus with a certain number of neutrons and protons…’

‘And electrons spinning around them like little planets orbiting a star,’ Claire-Marie interrupted. ‘Hydrogen is a single proton with a single electron spinning around it,’ she said authoritatively.

‘Very good, Claire-Marie,’ Simon responded. ‘And what about Helium?’ he asked.

‘Two protons and two neutrons in the nucleus,’ the little girl replied, ‘with two electrons spinning around them.’

‘Exactly right, well done.’

The Doctor continued. ‘Not all elements are completely stable. Some of the really large ones can be split into smaller atoms which is what we call nuclear fission.’

‘Boom!’ John said loudly. He was laughing.

‘Listen to what Simon is saying, John,’ his mother rebuked. The little boy looked guilty and stopped laughing.

Simon continued. ‘One of the elements that can be made to fission is a heavy element called Uranium which has the chemical symbol U. There are two isotopes of Uranium one is called U 235 and the other is U 238.’ He looked around the room. ‘What’s an isotope?…Cally?’

‘An isotope is a form of an element that has the same number of protons but a different number of neutrons,’ Cally answered.

‘So you do actually listen?’ Simon said in mock amazement. ‘I did wonder.’

‘What about the bomb?’ Jayne muttered loudly.

Simon rolled his eyes. ‘Alright, here’s the trick,’ he began. ‘When you fire a neutron into an atom of Uranium 235 something clever happens. The big Uranium atom splits into two smaller atoms Xenon 140, and Strontium 94.’

‘So?’

Simon smiled again. ‘What do 140 and 94 add up to?’ he asked.

Claire-Marie annoyingly beat her big sister to the answer. ‘Two hundred and thirty-four,’ she said loudly.

‘Right again,’ Simon confirmed and drew the sum on the board. ‘So we had a Uranium atom weighing 235 and a neutron weighing 1 so we started out with 236 and now we have 234.’

‘There’s two missing,’ Cally said.

‘Exactly,’ Simon responded. ‘Not only do we have the Xenon and the Strontium we also have two neutrons left over. And that’s how an atomic bomb works.’

‘What the heck are you talking about?’ Jayne demanded to know.

‘Chain reaction,’ Simon stated. ‘You see every time an atom splits, it releases a bit of energy and also sends off two new neutrons which hit two other Uranium atoms which fission, release a bit of energy and leave two spare neutrons of their own. The number of atoms accomplishing fission doubles each time. 1, 2, 4, 16, 32, 64, 128, 356, 512, 1024, 2048, 4096… well you get the picture,’ he said. ‘If you’ve got enough Uranium, or another fissionable metal like Plutonium, you can get what we call an uncontrolled chain reaction which keeps on getting bigger and bigger until all the atoms are going through fission, throwing off a massive amount of energy between them.’

‘How much energy?’ Claire-Maries asked.

‘A few kilograms would produce the same amount of energy as thousands of tons of explosives. That’s why we measure nuclear fission explosions in kilotons.’

‘But Daddy said the bomb Serenity is dropping is like millions of tons of explosives going off at once,’ Claire-Marie stated.

Simon sighed. ‘Well now it gets a bit more complicated,’ he said. ‘There’s another kind of nuclear reaction called Fusion and that’s where instead of breaking atoms apart you stick them together. That’s how stars work.’

The Doctor drew another picture on the board. ‘If you smash tiny atoms like hydrogen together you can get them to fuse together to make bigger atoms like Helium. The problem is that although it produces a lot of energy when you fuse Hydrogen you can’t get it to happen unless it’s very hot like at the centre of a star.’

Simon finished drawing a simple picture of two atoms colliding and continued. ‘Years and years ago scientists on Earth-That-Was realized that a nuclear Fission explosion might be hot enough to make nuclear Fusion happen. So what they did was surround a Plutonium Fission bomb with two isotopes of Hydrogen called Deuterium and Tritium and set it off.’

He stepped away from the board. ‘Like they thought it would, the Fission bomb made it so hot that the two Hydrogen isotopes fused together to make Helium and that made even more energy, far more than Fission could make. Instead of being the equivalent of thousands of tons of explosives it was like millions of tons of explosives all going off at once.’

‘So a Hydrogen bomb is really two bombs going off at once?’ Cally asked.

‘No it’s really three.’ Simon said grinning at Jayne’s expression.

* * *

Above the Reaver Encampment -Unnamed Planet – 2520AD

At eight thousand feet Kaylee’s carefully put together fusing system which was stuffed into a small can riveted to the front of the steel crate detected it was at the right altitude and sent an electrical impulse to the circuit board she had wired up inside, itself connected to the somewhat modified EMP device in the box.

Several capacitors fired simultaneously triggering a small quantity of explosives wrapped around a metal ball. The metal ball was compressed becoming very dense just as a neutron-source fired into it the increased density of the plutonium core making it easier to get the chain reaction to begin.

The metal sphere began throwing off masses of energy and neutrons in all directions.

Surrounding the Fission core was a mass of Lithium-Deuteride. One trick of nuclear chemistry is that when exposed to neutrons Lithium fissions into Tritium so as soon as the fission process began in the plutonium it also began to generate its own fusion fuel for the next stage of the process. By the time the fission explosion occurred it did so surrounded by Deuterium and Tritium which inside the enormously hot environment generated by the Fission trigger began to fuse.

If you want to think of it this way, three explosions occurred. A hundredth of a ton of plastic explosive detonated causing a Fission explosion equivalent to ten thousand tons of explosive which itself caused a Fusion explosion equivalent to five million tons of explosives.

A flash brighter than a thousand suns lit up the whole area thrown off by a nuclear fireball.

A millionth of a second after detonation the nuclear fireball measured a hundred million degrees Celsius in temperature, far hotter than the core of a star. Within a thousandth of a second after that it was five hundred feet across throwing off a blast of lethal X-Rays and a wave of thermal radiation that was hot enough to give instant third degree burns to anyone in the open who was within ten miles of the point of detonation.

After the initial heat and light, the first thing to hit the ground from the detonation far above was a supersonic wave of pressure riding a quarter mile ahead of the fireball itself, which hit the Reaver encampment just offset of centre. Thousand ton spaceships were lifted like matchsticks and thrown out of the way by winds that made a hurricane look like a gentle breeze.

The fireball itself had cooled dramatically as it expanded so by the time it had grown large enough to reach the ground its temperature wasn’t much more than 10,000 degrees. Given that steel melts at only around 1370 degrees that mattered not so much.

The Reavers and their ships within the fireball were simply incinerated. They were spread out over an area a couple of miles across which found itself entirely caught within the blast. The fireball continued to grow eventually touching the ocean and sending huge waves of steam out to sea to accompany the small tidal wave that had been produced when the pressure wave had arrived seconds earlier.

The land burned, the sea boiled.

The thermonuclear fireball itself expanded until it was three miles across before fading. The blast wave went much further and would have been powerful enough to damage a ship grounded another ten miles distant. Hundreds of thousands of tons of material were sucked from the ground and the ocean into the vacuum left behind and went hurtling skywards, an enormous cloud of debris forming a vertical column into the sky.

Ninety seconds after it began to form, a mushroom cloud ten miles high towered above the unnamed world.

* * *

Twenty miles away Wash banked the Firefly transport so the four crewmen gathered on the bridge could see what they had just done. River had done her sums correctly and Serenity had been well clear of the blast when it happened.

Wash was the first to speak. ‘Did we do that?’ he said awestruck.

‘I reckon so,’ Mal stated dispassionately.

‘It’s pretty,’ River interjected. ‘A good display leaves the biggest firework until last,’ she said reverently.

‘How close did we get?’ Zoe asked.

‘Shadow watched the thing fall as long as he could. Guesses we got within half a mile of where we wanted to drop it,’ Wash replied. ‘Did we really do that?’ he asked rhetorically.

‘Think we got them all, Sir?’ Zoe asked unable to keep her eyes off the cloud.

‘You’re kidding right? Who the hell could live through that?’ Wash asked pointing. ‘Shadow scanned the whole planet and says they were all right there when we dropped it.’

The Captain took a deep breath. ‘Okay show’s over. Let’s get back into the black and be on our way.’

‘Yes, Sir,’ Wash replied readying the ship to climb to orbit.

Mal took a final look at the cloud. ‘Well one thing’s been made pretty darn clear today,’ he announced loudly. ‘We are not people you should fuck around with.’

‘We bring a whole new level to the word “overkill” Sir,’ Zoe agreed.

River was the last to look away. Whilst her eyes were fixed on the mushroom cloud her thoughts were fixed on the other device which lay locked up on Granite Gorge. ‘Brighter than a thousand Blue Suns,’ she said quietly.

River smiled.

Part XV