Five years after her divorce, Maika takes her adult son Masaru and his friend Kenta on a long-awaited clam-digging trip. After a cheerful afternoon gathering clams on the beach, she returns to the inn and catches the male scent she has missed on Masaru’s discarded underwear, driving her to masturbate. Kenta secretly watches her and uses what he saw to blackmail her. He calls her an old lady and toys with her like a sow, eventually dragging her beloved Masaru into his sordid game...