Maki Tomoda is a devoted wife completely infatuated with her husband, who affectionately teases her for her obsession while she enjoys playing shogi with her nephew, Masato, in their daily life. One day, her husband suddenly leaves on urgent business, leaving Maki alone with Masato. Long harboring secret feelings for her, Masato can no longer restrain himself when faced with Maki's vulnerable state and aggressively makes his move. Though Maki resists at first, the emotional void caused by her sexless marriage leaves her subconsciously shaken by his strong, commanding presence, and she eventually gives in. From that day on, a hidden lust begins to grow between Maki and Masato, gradually transforming their once ordinary routine into something forbidden and intense.