Sakamoto Kenichi lives with a distant relative, a girl named Izumi Rina, in the house he shares with his mother. Rina’s reserved personality, caring nature, and defenselessness from growing up in an all-girls school make Kenichi, who is troubled by his distance from others, aware of adolescent sexuality for the first time. Seventeen years old, Kenichi tries to hide the fact that he is living under the same roof with a girl the same age as him from his friends, but Mori Yuriko, his childhood friend, finds out, and the distance between them changes slightly. A love story that reflects a seventeen-year-old in the throes of a sensitive and volatile relationship.