While her husband is away on a business trip, Riho Kobayashi indulges in secret nightly masturbation after her sons fall asleep. Trying to suppress her moans, she believes she remains unnoticed—but in truth, her sons have already sensed her loneliness. Driven by a desire to ease her solitude, they quietly begin taking action without her knowledge. A poignant episode unfolds as Riho's hidden desires intertwine with her sons' tender concern.