Rieko, a mother, is invited by her son to go on a hot spring trip. Since she has never done so since marrying her husband, who is devoted to his work, she couldn't help but be happy. After arriving at a nice-looking inn, the two head straight to the hot spring. Rieko is enjoying the open-air bath in the refreshing sunlight. Meanwhile, her son thinks of Rieko as more than a mother, and he is planning to confess his secret feelings to her on this trip. At dinner, the mother is in high spirits after enjoying the food and drinks at the inn. Her son cannot resist seeing his mother's body peeking out from under her yukata hem and attacks Rieko. Her son falls into self-loathing. Rieko is in a daze for a while. After a while, Rieko finds her son looking lonely and returns to her room. Rieko stares at her son's profile, but when her eyes meet her son's she says she's sorry, hugs him and kisses him...