In the scorching heat of midsummer, Saho lives with her husband and his parents. One day, her husband's younger brother, Kenji, returns home after being laid off. Shunned by the family, Saho gradually grows resentful toward him. Yet, as her sweat-drenched body begins to stir Kenji's desires, he takes advantage of her husband's business trip to rape her. Though she struggles and resists in agony, deep inside, Saho finds herself drawn to Kenji. Before her husband returns, they unite once more. Their sweaty, suffocating tryst in the summer heat forges a new, forbidden bond between them.