Koichi, son of Tabuchi, a renowned company owner, nears 30 but remains lazy, jobless, and glued to his phone. Worried he’ll stay single, and hoping marriage might reform him, Tabuchi arranges a match with Nao, daughter of a partner company’s manager. Koichi’s thrilled to have a beauty like Nao as his wife, but Nao, pressured by Tabuchi’s influence, reluctantly agrees. Tabuchi forbids her from having sex, even with Koichi, until marriage. A year later, they wed. That night, Koichi’s eager to consummate, but anxiety leaves him limp. The next day, he leaves for a five-day business trip, leaving Nao with Tabuchi. She retreats to her room, masturbating to ease her pent-up desires, unaware Tabuchi’s hidden cameras catch everything. Their marriage was his scheme to claim Nao as his 'wife.' While Koichi’s away, Tabuchi trains her into a lustful daughter-in-law, craving his cock, ready for him to fuck her even after Koichi returns...