Ryan thinks he's found the secret to improving his modest physique, transforming him from skinny punk to brawny hunk without having to bother with the big, heavy weights in the basement -- a magic muscle cream that can make him the strongest man on campus.
Of course, before long the muscle cream falls into the hands of his younger sister and her friends. The girls proceed to misuse the product, experiencing greatly increased female muscle growth that transforms them into busty amazons, with big, bulky biceps and bulging bosoms. Ryan soon finds himself facing off against three young women who have each grown fantastically strong and more muscular than he ever dreamed he could be.
With the only way to catch up being to also disregard the instructions, Ryan takes a chance. But will it result in him outmuscling the girls, or dwindling to pee-wee size, with even less strength and muscle mass than he had to start?