Asked by the beautiful hospital director Reiko Goei to become a tester for a new drug, Sora agrees to "muff" dive right in. He then moves to a special ward where he meets Yu Yagami, the delicious head nurse of the testing unit. Bored and alone, he decides to snoop around on the hospital computer where he stumbles upon information on the lustful, sex addicted nurse, Hiyori Kisaragi.
Sora edges towards a friendship with Hiyori, however to his surprise; Hiyori has something much more pornographic in mind than just being friends. "For my experiment, I want you to play with me!" says Hiyori. But experiments can sometimes lead to so much more.
