Psych House is a special home established for individuals who have awakened to supernatural abilities known as Psychs. The story begins when a young woman named Kotone is caught shoplifting by her eccentric new classmate, Nemuru. Kotone has been secretly using her teleportation power to steal food because her mother is ill and in the hospital, leaving the family with no money. However, Nemuru is not an ordinary student; his Psych allows him to change his size at will. Rather than exposing her, he reveals his own secret and invites Kotone to leave her old life behind.

Nemuru brings Kotone to the eponymous Psych House, a communal residence set up by the government to monitor and house people with these powers. There, Kotone discovers a small community of other psychics who live together under one roof, navigating the challenges of their extraordinary abilities while trying to lead ordinary daily lives. The narrative focuses on this supportive, almost familial environment, offering a slice-of-life take on the superhero genre.

The main characters include Kotone, a girl struggling with guilt and desperation who learns to use her powers for creation rather than crime, and Nemuru, a mysterious and enthusiastic boy who acts as a recruiter and caretaker for the house. The story is set primarily within the walls of Psych House and the surrounding city of Yamanashi Prefecture, blending mundane high school life with low-stakes supernatural shenanigans.

While the series is short, it contains several notable narrative arcs. The introductory arc covers Kotone's recruitment and her initial reluctance to trust the group. A subsequent arc features a game of tag using their various Psychs, serving as a bonding exercise for the residents. Another significant storyline involves the housemates working together to throw a welcome party for Kotone, during which she learns to harness her teleportation ability for more practical and joyful purposes, such as party decorations. The overarching, and ultimately unresolved, goal is the search for a healer-type Psych user who might be able to cure Kotone's sick mother.