Lieutenant Helen Dawes awoke from long haul sleep with a groan. The cover of the pod swooshed up and she clambered out, blearily. Functioning on autopilot, she slid on her grey jumpsuit, and put on her converse.

“Computer, why the fuck am I awake?”

“Anomalous material in vent 4d.”

“Fucking brilliant”

Dawes looked at her watch. It was months before she was due back on Earth. Some shit was in the vents, and she’d be woken up early to deal with it. Fuckin’ a.

She wandered down steel-panelled corridors, her thin, bony frame occasionally bumping against the walls when she couldn’t be bothered to steer herself. This was bullshit.

Rubbing her eyes, she clambered up the ladder into vent 4d. She grabbed a torch from the wall, and crouch-walked forwards through the vent. It was pitch black, bar the beam of light that shot down the thin corridor. She turned left, right, then left again, following Computer’s efficient, oddly terse instructions.

Suddenly, she had no need for the torch – she saw a bright, ominous green glow ahead. She put it in her breast pocket. At the end of the vent, there was what looked like a crystal throbbing, pulsing. She cautiously approached it.

“Computer – scan.”

“Structure is crystalline. Reacts strongly with metal.”

Sure enough, the metal around the crystal was buckling and bending, slowly folding outwards.

“Shit. This’ll eat the ship”, Helen said, to no one in particular. She moved to grab it.

“Alert! May respond to human tissue”

“Well I’ll be fucked if this ship goes under, so we’ll have to cross that bridge.”

Computer said no more.

Helen grabbed the crystal and, clutching it to her chest, turned to leave the vent.

Instantly, she knew something was wrong. She could feel a hotness in her chest, and her the front of her jumpsuit glowed slowly green. “What the-” her jumpsuit pushed forwards. Something in her chest was growing.

Helen unzipped the top of her jumpsuit, and stared, agog. Her tiny breasts appeared to be…getting bigger. They were pushing ever so slowly forward, against her white vest top. She’d always secretly fantasized about a bigger chest, but…not now, not like this. Shuffling forwards, she moved more quickly through the vents.

As she moved quicker, her breasts began to swell further, growing larger with each step – the crystal was obviously doing something to her, something Computer had tried to warn her about. Her breasts now poked an inch out in front of her, and looked very pert and full. She kept moving.

She made the first turn, and for the first time noticed her breasts pushed into her knees when they came up to her chest. She looked down, and saw her growing, swelling tits were now two inches straight out. “Christ, that was fast”. She needed to get this thing away from her, but she couldn’t drop it. Her breasts bulged, and she felt very thankful she wasn’t wearing a bra. She zipped her jumpsuit up to the top, trying not to think about her swelling orbs, and how arousing she found it all. She crouch-walked through the vent, taking the next turn.

In this corridor, her breasts really started to swell. Clearly exposure to the crystal was accelerating the effects. Her legs started to be pushed away from her as she crouch-walked down the vent – her breasts were bulging, surging forwards, bumping against her knees. She looked down, and saw large mounds pushing forth from her jump suit. Although she’d zipped it up to hide the effects, it only made them more pronounced, as two swollen melons stretched against the zipper. Everything was holding firm, but she didn’t know for how long.

She made the next turn, her breasts swelling and growing against the stretching jumpsuit. She suddenly realise she could feel the air on her ankles. Her bulging tits, now a full five inches in front of her in two big, pert orbs, had pulled the rest of her jumpsuit up to accommodate her swollen bosom. Helen started to feel very claustrophobic. She could still fit in the vent, but if her tits got much bigger, it was going to start feeling very tight in there.

As if in response, her breasts surged forwards, galvanised by the crystal, and stretched and pulled against her jumpsuit. They looked like large melons, pulling the top of her jumpsuit tight as they swelled forth. Her crouch walk was becoming impossible, as her breasts took up six inches in front of her. She went to hand and knees, as her knees were just bumping into her big tits each time she tried the old method. They wobbled with each knock, something she noted turned her on more and more each time it happened.

Hands and knees made moving slightly quicker, the crystal’s glow leading her in the right direction. It was only when her breasts hung down that Helen realised how big they’d become. Luckily the jumpsuit was keeping them in for now, but they swung massively in front of her, like two huge udders, only kept in check by the increasingly tight jumpsuit. Her breathing started to get tight. Her tits were getting so big.

“Computer, how far to the vent entrance”, Helen muttered.

“100 metres”

That was doable. As her breasts swelled forward, buckling her jumpsuit and putting the zipper to the test, she crawled increasingly quickly down the corridor, seeing her breasts engorge beneath her. As they enlarged, they began to wobble maddeningly with each move of her hands. Her jumpsuit pulled up further at her ankles. They were really big now – around eight inches, straight down. They were getting really heavy, and dragging her back down. She rested for a moment, leaning down, and noticed with horror and arousal that her swollen chest touched lightly against the base of the vent. If they got much bigger, she wouldn’t be able to move in her. The thought spurred her on.

She wobbled her way down the corridor, until she could see the entrance to the vent. It looked perilously small for her new, hugely busty figure. She jiggled her way up close, growing all the time, her jumpsuit now bursting at the seams. She took a deep breath, and felt her zipper pop down a couple of notches. She ignored it.

Quickly, she lowered her legs down, and went to climb down the ladder. Suddenly, she realised she had to have both hands free. She went to put the crystal in her pocket, before realising logistically that would be difficult – there were two huge watermelons poking ten inches out in front of her. She closed her eyes, realising what she had to do.

As quickly as she dared, she reached for the zip at the top of her jump suit, which was beginning to quiver under the strain. She almost hear its gratitude as she slid it down, exposing what seemed like miles of cleavage. “Can’t believe I’m doing this”, she muttered, as she slid the crystal in the only place that she could – between her massive tits. Its glow increased. “This may have been a really bad idea”, she thought to herself.

Hands now free, she began to climb down the ladder. This was difficult, as she couldn’t see down beyond her humongous breasts, which were growing with a newfound vigour. Three rungs down, she stopped. She was stuck. Her now rather tremendous were wedged at the top of the vent, and still growing. She panicked, and swelled uncontrollably into the gap. She could see her cleavage expanding as her breasts bulged upwards, like boiling water bubbling over. The crystal became ever more squeezed as her huge tits pressed together, removing any remaining gap between them. They were truly massive, and still growing.

Helen began to panick. She removed her feet from the ladder below, and just hung in midair, suspended by her vast chest. She could feel her jumpsuit had ridden up to the middle of her shins, so much of it pushed forwards by her burgeoning bosom. She looked down and all she could see was tit, as far as the eye could see. Tit and and that damned crystal…the crystal! She suddenly remembered it had properties beyond making her tits ludicrously big!

She noticed it was being enveloped by her bulging bust, which was growing upwards with every passing second. She felt her jumpsuit zip stretching to its maximum as her huge tits swelled outwards. Quickly, she reached down and yanked the crystal out of her cleavage, before it was swallowed completely. Flailing with her arms, which seemed tiny compared to her now twelve-inch straight out protruding tits, she moved the crystal to the metal at the lip of the vent, which duly bent backwards like the petals of a flower, allowing her huge, growing tits to surge forwards, taking up the space. She continued the process, until her colossal bust was only resting on the retreated lip of the vent. Placing her feet back on the ladder, she unwillingly slid the crystal back into her cleavage, and clambered down the ladder.

This was easier said than done, as her titanic chest wobbled and shook and ballooned with an all new enthusiasm at being reunited with the crystal. With each rung, her cleavage grew and grew. She had to lean back from the ladder, as her huge tits were bouncing on each rung. She could barely hold onto it, as they kept growing to the side, slowly nudging her arms out of the way. Their circumference was truly incredible. Eventually, she reached the floor, breathing a sigh of relief. As a reward, she wrestled with the zip on her jumpsuit, eventually pulling it down over her gigantic, swelling bosom. With a huge flop, her colossal breasts swung out, barely covered by her vest. Helen tied it at the bottom to try and contain her enormous breasts, but she knew it wouldn’t last. She removed the crystal from her cleavage, and briefly took stock.

“I need this off the ship. Computer! Thoughts?”

“Airlock?”

Helen ran off with a bounce. At least, she tried to run, but her monstrous bosom made this a challenge. Her fifteen-inch breasts swelled and bounced as the fabric on her vest began to strain – it wasn’t built for such containment as her jumpsuit was. Her breasts ballooned like two huge beachballs on her chest – incredibly round and perky, but also massive and bouncing. With each step they grew bigger, even when not directly put in contact with the crystal. The effects were obviously ongoing.

Helen tottered down the corridor towards the airlock, her chest growing more enormous by the second. “I’m barely going to be able to fit down here if this carries on!”, she thought, both alarmed and aroused. She began to stagger as her chest grew heavier and heavier, swelling out of the cradle she’d made by tying the bottom of her top together. Looking down, all she could see was cleavage, as her massive seventeen-inch bust squeezed into her tight vest, bulging out to the side and to the top in enormous swollen orbs.

Eventually, she reached the airlock doors, and realised with horror that she couldn’t reach the opening button when facing it. In the bouncing shimmy down the corridors, her breasts had swelled to a full twenty inches in front of her, and they bulged into the wall when she tried to face it. The very touch of her huge nipples against the wall drove her wild. She turned to the side, swinging her huge tits to the left, shuddering as her nipples brushed against the wall. Her top was stretched to beyond maximum capacity. She could see rips and tears in the fabric. She couldn’t see her feet without a complex array of mirrors.

Now side-on, she opened the first airlock door. She was supposed to have a space suit on at this point, but the very idea was laughable. She wouldn’t have been able to fit one breast inside, let alone two and the person attached to the them. The thought turned her on more than it should have, given the circumstances.

She wobbled into the airlock, placing the crystal on the floor. She turned to go…then had a quick idea. After a quick, almost-shirt-shredding detour, she returned, and closed the outer door. She was inside the ship, ready to jettison that terrible thing. She could see the floor buckling. She pressed the “open outer door” button.

A howling wind. Both doors were open. She noted with horror that her breasts, forever swelling, had gotten so big that it had pressed another button without her consent, opening both doors! The crystal disappeared into space, and Helen felt herself shooting feet first into space. She closed her eyes, and waited for the end.

…

She opened them, and still heard the roaring. Looking up, she saw two enormous balloons keeping her afloat. She felt a rustle as her jumpsuit was wrenched from her, disappearing into the void. Looking up again, she saw the doors had tried to close, trapping her colossal tits between them. She was pinched, held by her enormous knockers, as space roared behind her. Swinging her legs, she managed to kick the “close” button, and the roar subsided. Finally, she was safe.

Helen stood into the science laboratory, 10 minutes later, bigger than ever. Her breasts appeared to have stopped their growth on a mammoth 22 inches straight out. Her top had slowly surrendered on the last bout of swelling, and hung, limp at her side.

She looked proudly at the container she had constructed. Inside it, hanging in zero gravity, was a tiny chunk of the crystal she’d chipped off it before it was jettisoned.

“Hopefully these effects aren’t permanent”, she said to herself, hefting one of her tremendous breasts. It was so heavy, pert and swollen. She doubted she could have gotten much bigger anyway.

“Just in case I go back to normal”, she smiled.

She sat down on a chair, which promptly broke beneath the weight of her gargantuan bust.

From her position on the floor, seemingly submerged beneath two small beanbags, she sat upright, dragging her perky, huge tits with her.

“Computer, will these…go down? I’m not sure I’m going to fit in the cryo-tanks”

“…yes. In time.”

“How long?”

“168 hours”

“A week?! What am I going to do for a week?!”

Absentmindedly rubbing her nipple, Helen was reminded how incredibly horny she was.

“Ah yes”, she thought, sliding her hands over her nippes, which she could only just reach.

“Computer, go to sleep mode”

“Good night, lieutenant”

“Good night.”