After the memorial service for her husband's first death anniversary, Sumire Shiratori shares drinks and fond memories with her brother-in-law Hiroshi. As the alcohol flows, Hiroshi—long harboring feelings for her—gives in to desire and the two become intimate. At that moment, her other brother-in-law, Ryo, returns home. Discovering them in a compromising state, Ryo demands an explanation, but an unexpectedly defiant Sumire lashes out and begins provocatively touching her own genitals, spiraling out of control. With pent-up lust unleashed, Sumire enters Ryo's bedroom, bares her voluptuous body, and flaunts an explicit masturbation session before him... A scorching tale of passion and desire entangling siblings, charged with raw intensity.