A household consisting of a father and his three sons lives next door to a beautiful young widow named Ryouko, who lost her husband two years ago. The two families have maintained a close bond ever since their spouses were close friends, and the boundary between their homes has always been nearly nonexistent. One day, Ryouko visits her neighbors with souvenirs from a recent trip. However, although she sensed someone had just been there, the house appears completely empty. Scattered about are crumpled tissues left in disarray. Among them, Ryouko finds her missing panties. When the youngest son realizes she's discovered them, he awkwardly apologizes. Though they agree to keep the incident a secret between just the two of them, this moment threatens to shatter the once-harmonious relationship between the families...