Holly had just arrived back from her shopping trip, having place her bags inside she headed down the path to her sisters lab. As she approached she noticed that the door to the lab was swinging open, a careless and unusual mistake for her sister to make. But her attention was quickly drawn away when she noticed the scraps of clothing scattered through the pig pen, had their washing somehow blown into the pen and been torn up?
Having jumped the fence Holly picked up a scrap of clothing, to her dismay it was a piece of the shirt Grace had been wearing when she left, what was going on? "Grace? You there?" called Holly tentatively as she approached the pig shed, as she entered her nose wrinkled at the smell of semen, as her eyes adjusted to the dim lighting she saw the source, a huge sow lay on the ground before her, cum dribbling from it's gaping sex. "The fuck?" exclaimed Holly, she hadn't seen this pig before, it wasn't one of theirs, that's when she noticed the still human looking hair on the top of the pigs head, looking first at the sow, then at the piece of shirt in her hand she put two and two together, screaming she realized the pig was Grace.
Holly ran to her sister, "what happened!" she cried, she received only a grunt in reply as the sow rose to its feet and nudged its face against Holly, it's swollen teats swaying all the while. "we can fix this, I know you're still in there..." though she said the words Holly wasn't sure she believed them, there was no trace of humanity in the pig's gaze. She turned to leave, she had to call for help, but she only made it a few steps before her path was suddenly blocked by a huge shape. Their breeding hog Boris blocked her path, but he had changed, having mated with Grace the serum had affected him, he was twice his original size and between his legs his testicles swung like two soccer balls, already bloated with cum despite having only just emptied them. "Oh fuck.." was all holly manged to say before he was upon her.
Boris, huge and powerful, had little trouble overpowering Holly, he smashed her to the ground and in a matter of seconds ripped her shorts away with his gnarled teeth, she quickly regretted not wearing her underwear today, as she was now fully exposed to Boris, as his huge cock flopped around her entrance. She twisted around and tried to crawl away, but in doing so she was in prime position for Boris, and with a single thrust he was inside her, his cock smashing through her hymen and pressing against the entrance to her womb. The air having been driven from her lungs Holly could only gasp as Boris began to mate with her, his balls slapping against her ass with every thrust.
As Boris thrust away his cock leaked precum, squelching inside Holly as it lubed her up, but it was doing more than just lubricate, Holly's pain was starting to turn into pleasure. "Ooohhh, why does this feel good?" moaned Holly as with every passing moment her disgust and pain was further replaced with pleasure and a growing attraction to her new mate. "Mate" as the thought occurred to her it sounded quite attractive, yes Boris was her mate, and she was one of his sows. "No! No! No!" what was happening, her thoughts were turning against her. But Holly couldn't fight her growing lust anymore, she gave in to her desires, beginning to match Boris's thrusts. As if it had been waiting for her submission, her transformation began.