During a hot summer, stepsisters Tsubomi Mochizuki and Riisa Kisaragi stay at their husbands' family home. With their husbands away playing golf and constant nagging from their stepmother, the two women are stuck with nowhere to go. Confined together, their relationship as sisters-in-law slowly deepens into something more intimate. In ordinary spaces like the tatami room, bathroom, and veranda, they share slow yet intense lesbian moments. Their damp, sweating bodies entwined with pure emotions, a secret affair unfolds, lasting until summer's end. A beautiful yet bittersweet erotic summer tale of lesbian desire.