After marrying the eldest daughter of the Adachi family, the easygoing son-in-law lives a carefree life much like a typical "Masaosan." His mother-in-law, Yuko, constantly feels frustrated by his apathetic attitude. One evening, after a family dinner, while everyone is spending time together, she becomes furious seeing him completely absorbed in a handheld video game. Though she later regrets her outburst and decides to apologize to him the next day, her husband suddenly leaves for drinks with a friend. Left alone, Yuko retires to bed. In the middle of the night, she wakes up sensing someone nearby—her son-in-law has entered her room. With bloodshot eyes, he lunges at her, grabbing her body and sucking her nipples. Shocked and struggling to resist, she finds herself overpowered by his strength. It had been a long time since she'd been intimate with her husband, and against her will, she begins to grow wet. He thrusts his hard, burning cock deep inside her, causing her to momentarily lose consciousness. Overwhelmed by his intense, relentless thrusting, she can no longer suppress her pleasure. As he pulls out, he cums hard, spilling his hot load all over her buttocks. Dazed by a level of physical ecstasy she's never experienced with her husband, Yuko remains lost in sensation, body and mind completely consumed. The following night, as Yuko walks into the living room, she finds her son-in-law looking depressed. He apologizes sincerely for the previous night, and she responds by admitting she'd also been too harsh. Gently embracing him, she kisses him softly. Fully aware of what they're doing, she whispers to herself that it's just this once—just tonight—and slowly presses her lips against his again.