After remarrying, her husband is away for work, leaving Risa to live alone with Yoshio, her stepson. As Yoshio gradually matures into a man, Risa begins to see him as a romantic interest, causing her inner confusion. Bound by their stepmother-stepson relationship, she struggles to suppress her feelings. Meanwhile, Yoshio also harbors secret desires for Risa. At the urging of his friends, he fantasizes about Risa writhing in lust, and the two wrestle with their forbidden emotions—how their relationship will unfold and what fate awaits them remains to be seen.