Mary grabbed one of the vials from the myriad of choices, her eyebrow raised slightly at the prospect of liquid being able to physically transform you. As she glanced at the dark blue colored liquid, she caught sight of a standard decal for a man on the side, like the one you would see on any men's restroom in the world. Smirking again she uncorked the vial and took an experimental sniff, almost recoiling from the musty aroma that the liquid had.
"I must be crazy to think these will work," she muttered to herself, almost recorking the vial and walking away from the whole thing. Then again, she figured that it couldn't hurt to try just one, and deep in her mind she was somewhat curious what a transformation into the other sex might bring about. Shrugging her shoulders, she leaned back and drank the whole of the vial in one quick shot, wiping any excess liquid from her mouth as she emptied the vial. Placing the stopper back on the vial, she placed it back in the drawer and waited a few seconds for the effect to begin, only to feel foolish a moment later when nothing happened. Shaking her head at her own stupidity, she started to walk away before giving one last glance back at the vials, just in time to see the vial she had just drained finish filling itself back up with the same blue liquid.
She paused a moment, wondering exactly how something like that could happen, when she felt a sudden heat come over her body. Fanning herself with her hand she started to take her clothes off, only to be overcome by an increasing pain sensation that filled her entire body. She doubled over and collapsed, grimacing and screaming as the energy coursed through her body. She could feel it stretching and contorting every bone along her frame, as she suddenly grew eight inches in a matter of seconds. Looking down in fear, she watched as her blouse ripped slightly along the seams from the sudden growth, and her hands turned into larger, rougher, and more callous than what she was used to. Pinpricks crisscrossed her skin as she saw dark hair thinly grow in along her arms and, as she glanced down at her expanding legs and feet, all along those appendages as well. Slowly she watched in horror as her feet grew out of her shoes, causing the small heels she had been wearing to burst out into several pieces.
She could feel muscles growing all over her newly expanded body, as she struggled to remove the remains of her clothes, leaving only her bra and panties on. She glanced up in a nearby mirror and saw her face morph, becoming more angular and hardened as it became more masculine. Her shoulders broadened while her wide hips narrowed at the same time. Her long, flowing brown hair slowly receded into her head until it became a shorter, coarse buzz cut, as a five o clock shadow formed across her new face. Feeling a pain in her chest, she watched in fascination and a growing amount of pleasure as her C-cup breasts slowly shrank into her chest, melting until they became nothing more than part of her impressive pectoral muscles. She vaguely thought to remove her now useless bra as the final change came over her. Grunting in her new deep baritone, she couldn't help but reach down and grab at her nether regions, not surprised to find her vagina quickly closing up and her clitoris growing in her hand. Before long she had a six inch shaft that she was pumping up and down, grunting out loudly once more before a shot of cum blasted itself out of her new balls and onto the floor in front of her.
Standing up slowly, and getting used to the new proportions, Mary was amazed at what the vial had done. Eyeing them again, he saw the pink liquid next to the blue one that would likely transform him back, while the blue one next to it had been refilled. What would happen if a man took more of the male vial? He also though to all of the other vials in the kit, and wondered what exactly they could do as well.