Tomoka, a married woman, lives with her husband's family and struggles daily, exhausted yet persevering. One day, her brother-in-law, a writer burdened by work troubles, temporarily returns to his parents' home. His career and personal life are both in disarray when one night, he accidentally witnesses his younger brother and his wife engaging in intimate relations. Overcome by the sweltering summer heat and captivated by her sweat-drenched body, he loses control and forcibly takes his sister-in-law, Tomoka. Strangely, Tomoka finds herself drawn to him. During the sultry tropical nights, the two become entangled in a passionate affair, drenched in sweat and bodily fluids, craving each other relentlessly.