Bethany is a tomboy country girl working at a dairy farm that is about to be shuttered. Her boy like appearance was always something she hated about herself but loved the country life and working with the cows. Her boss is a few years older than her, and she liked that he had confidence in her to run the farm for a short time before a nasty divorce made him sell off the herd.
With her life savings and John's last bit of money from selling off some equipment she decides to help John save the farm and buy back some of the cows. Beth then finds out that John's cousin is a scientist working on a serum to improve fertility and milk production in cows. In a secret deal, John gets help from his cousin and a dose of the formula to help his farm come back from near bankruptcy.
Bethany is overly excited about buy back some of the cows and without realizing it takes the serum and finds herself the test subject. She now finds herself becoming more feminine with her appearance and what she lacked before comes to her in abundance. Not wanting her newfound body to go away, she holds off on taking the antidote but finds herself needing sexual desires that she never had before. Thinking its normal she soon finds out that she likes the idea of being a dairy cow and now wants to fulfill her desires and become pregnant. Beth gives into her desires and asks John to become her bull and give her what she wants.