Kozue Takama, a Japanese woman with red hair and brown eyes, lives with profound loneliness due to her husband's constant absence. She works part-time at a flower shop owned by Mai Katsuragi, her old school friend and senpai, though Kozue struggles to distinguish flower varieties despite her job. While at the shop, Kozue observes Mai and Tsutomu—Mai's brother-in-law and coworker—sharing a connection extending beyond family ties. Envious of their bond amid her isolation, Kozue receives Mai's permission to pursue romance with Tsutomu. This arrangement entwines Kozue, Mai, and Tsutomu in a complex dynamic shaped by their shared emotional needs and desires.