Tsugumi, a girl living with her father in a single-parent household, is often alone because her father is always working. Around this time, she is approached by a middle-aged man who lives nearby and becomes close to him. However, the man starts playing with Tsugumi's nipples and eventually engages in sexual acts under the pretense of 'play.' Now, having sex has become routine, and the acts escalate further as his friends also come to the house and have their way with her…
