There is a girl whom Yuuta likes. One day, while lost in his thoughts whilst staring at her picture on his handphone, he is seen by his cousin, Kei. Kei mistakenly thinks that he is despondent over poor performance on his mock exams, and so goes over to make fun of him. To rebuke his slovenly attitude, Kei treads on his groin. However, as she feels his manhood stiffening beneath her foot, she too starts to feel aroused…