One day, Shota is suddenly threatened and is rescued by a passing female college student named Kei. She has an unexpectedly stunning figure, especially her large, voluptuous breasts that immediately catch his eye. Smitten at first sight, Shota is taken to her home to treat his injuries. But instead of gratitude, Kei begins a series of increasingly bold and naughty pranks on him. While cooking together in the kitchen, she lets him grope her breasts, and later in the bath, she gives him a blowjob—leading to various erotic encounters. Eventually, the two end up spending a late night together at Kei's place.