One of Asia's largest illegal weapons and drug trafficking organizations, disguised as a food company, is the Hou-un Group. The group's true heir, Chaeran, mysteriously disappeared two years ago. Her husband, Kangwoo, had kept her disappearance a secret, but with the release date of a new drug fast approaching, the truth is eventually discovered by his father-in-law—the chairman of the Houun Group. Chaeran was the only person in the company capable of perfectly replicating the drug’s formula. Her disappearance posed a massive corporate loss, forcing Kangwoo to finally start tracing her whereabouts. Before long, Kangwoo learns that Chaeran may be living in a small 1K apartment in Setagaya, Tokyo. However, when he arrives, Chaeran is already gone—and instead, he comes face-to-face with a man named Dohwa, who claims to have been Chaeran’s housekeeper. Thus begins a precarious love story between two men, born from a strange and desperate quest to find one woman—set in the rainy heat of a sweltering summer.