Mio, who divorced ten years ago, raised Yuki single-handedly. To keep him from feeling pitiful, she worked tirelessly, and before she knew it, Yuki was in his graduation year. While child-rearing had calmed down, Mio found herself without a goal. However, Yuki invited her on a hot spring trip to express his gratitude for everything up until then. Mio and Yuki set off on their graduation trip for two.
