Chisato lives with her husband and son, Satoshi. However, her husband is often away on business trips and hardly ever at home. One day, Chisato realizes that due to the recent continuous rain, she has washed all of her underwear and reluctantly decides to spend the day without any. Feeling a chill in her lower half, Chisato can't help but feel restless. Noticing his mother's unusual behavior, Satoshi comes up with a little prank…
