A man in his thirties, already broken by love, watches the person he's been quietly protecting move on with someone else. The movie doesn't pretend this gets easier or that timing fixes anything. It sits with the specific ache of loving someone who was never yours to begin with, then asks if that love still means something when it's the only honest thing left.

Picking up after the final episode of Sekai Ichi Hatsukoi 2, the film finds Takafumi Yokozawa heartbroken over his longtime friend and first love, Masamune Takano. He tries to drown the pain in alcohol, drinks until he blacks out, and wakes up naked in a hotel room. Waiting for him is Zen Kirishima, a coworker who runs the shounen manga magazine Japun. Kirishima took compromising photos the night before and uses them to make Yokozawa go along with whatever he wants: drinking together, pricey dinners Yokozawa cannot afford, even visits to the Kirishima home. As he spends time with Zen and his daughter Hiyori, Yokozawa slowly starts to let go of his broken heart. The story is a romantic comedy-drama adapted from a BL light novel.