As a newlywed, her daily life with her husband, Yoshiro, is dull and leaves her sexually unfulfilled. One day, her brother-in-law, Masao, visits the house, and she becomes captivated by his huge cock. From that moment, she can't stop thinking about Masao, whether she's asleep or awake. Obsessed with masturbating while fantasizing about him, her longing grows unbearable. When Masao visits again, she finally takes action...!?