Tatsuya enjoyed living alone again while his wife was away on a home visit due to her pregnancy. But after a week, loneliness began to creep in, and he started craving human connection. Just then, his sister-in-law Tsubasa unexpectedly arrived, offering to help with housework. Tatsuya happily welcomed her warm presence. However, Tsubasa's true intention was to relieve Tatsuya's pent-up desires while his wife was away. Unaware of her motives, Tatsuya relaxed in the bathtub—until Tsubasa suddenly appeared before him, completely changing the situation.