Rôma Oriya is a high school student and member of the kickboxing club. He exhibits a consistently apathetic attitude towards training and practice, neglecting his responsibilities. This lack of commitment jeopardizes the club's existence, threatening disbandment due to insufficient members for team tournaments. His lazy demeanor and frequent involvement in fights result in recurring injuries and draw persistent reprimands from Tamaki, his childhood friend and fellow club member.

Rôma and Tamaki share a long history, initially defined as a purely physical arrangement devoid of deeper emotional ties. Their dynamic fractures when Tamaki proposes ending their sexual relationship following Rôma's refusal to use contraception, creating emotional distance. Concurrently, Yuri, another student aware of their situation, attempts to mediate between them. During this mediation, Yuri develops concealed romantic feelings for Rôma, which she later confesses, initiating a new sexual relationship between Yuri and Rôma.

Outside kickboxing, Rôma pursues an interest in art. During a supplementary art class, he produces a nude drawing of another student, Misaki. This artistic act, combined with Rôma physically confronting a stalker targeting Misaki, prompts her to respond with seductive advances. Later, Tamaki discovers an old sketchbook linking their shared past memories, intensifying her dissatisfaction with their current platonic childhood friendship status.

A mysterious element surrounds Rôma. Multiple individuals within the school environment—including students and teachers—report experiencing unexplained memories or an unsettling sense of familiarity associated with his presence.