Nozomi divorced her husband 10 years ago and raised Naoya on her own. Despite being a single mother, she worked hard not to make him feel sorry for her, and before she knew it, Naoya had graduated from university. With parenting coming to an end, Nozomi felt a sense of relief but also a sense of emptiness from losing her goal. One day, Naoya invited her to a hot spring trip. Nozomi and Naoya set out on a graduation trip for just the two of them.