Three art students sharing a rundown apartment complex in Tokyo find their close friendship tested by the arrival of a shy but gifted young painter. Yuta Takemoto, a gentle architecture student uncertain of his future, and Shinobu Morita, a brilliant but eccentric older student who vanishes for mysterious high-paying jobs, both fall in love with Hagumi Hagu Hanamoto, a diminutive 18-year-old prodigy who looks much younger than her age. While Morita expresses his affection in baffling ways that frighten Hagu, calling her mousey and constantly photographing her, Takemoto hides his feelings and tries to be a supportive friend.

The circle expands to include Ayumi Yamada, a pottery prodigy known as the Iron Lady for her strength in both ceramics and unrequited love. Popular with many men, Ayumi is hopelessly devoted to the third roommate, Takumi Mayama, a focused and serious design student who sees her only as a dear friend. Mayama instead pursues Rika Harada, a beautiful but emotionally wounded older woman who runs the architecture firm she founded with her late husband before his death left her physically disabled and grieving. Professor Shuji Hanamoto, Hagu's guardian and Rika's old college friend, watches over the group as they navigate the messiness of young adulthood.

Over the course of their college years, each character grapples with love that is not returned. Ayumi endures the pain of watching Mayama devote himself to Rika, even as he relies on Ayumi as his closest confidante. Hagu, initially too timid for close relationships, slowly warms to the group but struggles to understand her own feelings for the unpredictable Morita. Takemoto, feeling inadequate compared to Morita's genius and Mayama's drive, embarks on a solitary bicycle journey across Japan after his graduation is delayed, searching for purpose and the courage to confess his love. Morita, torn between his ambition for his art and his affection for Hagu, makes difficult choices about leaving for overseas opportunities.

Set against the backdrop of art school, where creativity and insecurity intertwine, the story follows these five friends through graduation, job hunting, and the painful but necessary process of letting go. They learn that love takes many forms, not all of them requited, and that growing up means accepting loss while finding one's own path forward.