It has been 10 years since she married Hiroshi, a childhood friend of hers since they were students, and lately Hiroshi seems to have grown cold towards Miki, and they go out drinking every day. As her life with her husband diminishes due to temptation and emptiness, she becomes increasingly lonely. Her emotional support comes from her father-in-law, Tooru, who lives next door. The love he had for Tooru, who was his homeroom teacher when he was a student and always treated him well, comes back to him. Before she knew it, Miki, who had been subtly seducing Tooru, made up her mind and headed to her father-in-law's bedroom...