Kazuya Hasekawa arrives at the prestigious Ryokuto Academy, a private all-boys school, hoping to escape a painfully awkward home life. His beloved older brother has just married Sumire, the woman Kazuya secretly loved, making it unbearable for him to remain under the same roof. However, his plan for a fresh start is immediately complicated when he is assigned to live in Greenwood Dormitory, a building with a grim reputation as a former insane asylum, now known as the campus home for its most eccentric students.

Kazuya’s troubles deepen when he meets his new roommate, Shun Kisaragi. With his delicate features and long hair, Shun is so beautiful that Kazuya initially believes he is a girl, a misunderstanding that ends in embarrassment when he discovers the truth in the boys’ bathroom. To Kazuya’s horror, the rest of the dorm was aware of the ruse and had been betting on how long it would take him to find out. Living next door are the dorm’s charismatic but sadistic president, Mitsuru Ikeda, who seems to enjoy tormenting Kazuya as a way of toughening him up, and Mitsuru’s calm, intellectual best friend, Shinobu Tezuka, whose near-perfect demeanor hides a complicated family history.

Throughout the thirteen episodes, Kazuya gradually finds himself drawn into the absurd and heartwarming chaos of Greenwood, a place where a student lives in the same room as his motorcycle and a dorm mother keeps everyone in line. He struggles to adjust to his new life while also dealing with the fact that his well-meaning brother, Kazuhiro, is the school nurse. The narrative follows the everyday antics and growing bonds among the four main residents, from competing in an inter-dormitory film contest to confronting Shinobu’s jealous cousin, Nagisa, who tries to ruin his life. As Kazuya gets used to the madness of Greenwood, Mitsuru eventually steps down and names him the new dorm president. The series also develops a romantic arc for Kazuya as he falls for Miya Igarashi, a tough delinquent girl from a local high school, and navigates the challenges of dating her against the wishes of her childhood friend. Through it all, the young men of Greenwood turn their unusual dormitory into an unlikely home.