On a sweltering summer night, the oppressive heat wraps around the body, disrupting sleep. Shiori wakes up, glances at her husband sound asleep beside her with mild annoyance, and heads to the kitchen. She downs a glass of water, quenching her thirst as a few droplets spill from her lips, cooling her skin and accentuating her voluptuous figure clad only in a thin slip. Unable to endure the heat, Shiori absentmindedly begins touching herself. Suddenly, her son Yosuke returns from the bathroom and catches her in the act, instantly shifting the atmosphere in the room.