Yuu lives with her domineering husband. Though she loves him, her heart is drawn to his younger brother. Unable to suppress her feelings, she receives news that her brother-in-law will be staying at their home for a few days. Yuu decides to welcome him, though her husband seems slightly irritated. A few days later, on a night when her husband is away, Yuu drinks with her brother-in-law. Looking directly into his eyes, she confesses, "I've liked you for a long time." She tries to brush it off, but in the silence, she can hear her own heartbeat. Gazing into each other's eyes, they slowly share a kiss. Suddenly, her husband returns home. After that night, stealing moments behind her husband's back, the two secretly deepen their forbidden love. These secret encounters continue to stir Yuu's emotions ever deeper...