Sora, a high school girl who shoulders much of the household work after her mother’s death, strains her back carrying her sleeping younger brother and visits the school infirmary. While resting on the bed, she drifts off and wakes to find the strikingly handsome and musically gifted Arashi Tsukinose asleep beside her. Arashi, a world-class pianist who suffers from chronic insomnia, discovers that the sound of Sora’s heartbeat calms him enough to fall asleep. He proposes that she come to his apartment each evening as a paid sleeping companion, and Sora reluctantly agrees.

Their arrangement begins purely transactional, but Sora’s warm, family-oriented nature slowly draws Arashi out of his cool, isolated shell. Over the course of the manga, the two navigate the awkwardness of their unusual relationship while tackling school life, family responsibilities, and the complications of young love. A major narrative arc introduces Tamako, a flashy YouTuber and pianist who aggressively pursues Arashi, sparking jealousy and forcing Sora to confront her deepening feelings. Arashi, who spent much of his childhood abroad, initially struggles with Japanese romantic conventions, leading to a poignant scene where he admits he never understood the need to verbally “date” because he simply wants to be with Sora.

As their bond strengthens, their romance is exposed by a tabloid, and the ensuing media pressure causes them to temporarily distance themselves. In the climax, Arashi invites Sora and her entire family to his piano recital and delivers a very public proposal on stage, affirming his commitment. A brief epilogue jumps several years into the future: Sora has become Arashi’s manager, and the two work and live together as lifelong partners. The series concludes with their wedding, bringing a full-circle resolution to a story that began with a chance encounter in the school infirmary.