While his wife was away on an overnight trip with a friend, Kentaro indulged in the pleasure of living alone, using a long-hidden, treasured adult video as his stimulus. Intoxicated by the rare taste of freedom, he accidentally left the front door unlocked. At that moment, his sister-in-law Reiko dropped by for a visit, noticed the unlocked door, and entered the house to look for him. She unexpectedly stumbled upon Kentaro, who was completely absorbed in masturbation. Caught off guard by her sudden appearance, Kentaro panicked and struggled to regain his composure.