Koi wa Kataru ni, Ochiru Mono.

College student Ise Natsume possesses the striking looks of a handsome young man, yet beneath that exterior lies a quiet, expressionless individual with almost no friends and even less romantic experience. His solitary world is suddenly upended when he falls for Amano Haru, a classmate who is his complete opposite—bright, affectionate, and effortlessly charming. Natsume begins watching Haru from afar, but a concerned friend quickly intervenes with a harsh warning: Haru is an amoral pleasure-seeker who will do anything to get what he wants. Natsume initially dismisses these rumors, unable to believe someone so endearing could be so reckless. However, his illusions shatter when Haru boldly barges into his apartment, casually explaining that he needs a place to crash because his three simultaneous partners just discovered each other. The unexpected intrusion sparks a heated physical encounter between them, leading to an arrangement as casual lovers. While Haru is content keeping things purely physical, Natsume finds himself wanting more than just fleeting pleasure—he genuinely wants to date him, though Haru refuses to commit. What follows is a heartfelt story tracing how a slow-to-mature, handsome introvert and a beautiful playboy navigate their complicated dynamic, slowly transforming from mere physical partners into something far deeper.