Six months ago, an unexplained phenomenon caused a small minority of women around the world to develop a Z chromosome—and grow a new, thick feature. One of those women is Roy's best friend's mom, Mrs. Vasquez, and he's only found out by accident. And he's also about to learn what happens when he comes into contact with her...

Now with his groin more compatible to Z-positive women, Roy's learning to live in a world where big female bulges are the norm. From a Nigerian-American astronaut getting naughty for the entire internet to see to Mrs. Vasquez's friend, a pregnant gynecologist capable of poking someone's eye out, his desires are changing as his body wants more and more after that first, consequential encounter...