Arisa divorced her husband 10 years ago and raised her son Yuki on her own. - In order not to make him feel sorry for himself, he worked hard to pay for his education. - As a result of his efforts, Yuki was able to successfully graduate and find a job. - After finishing raising her children and feeling lonely, Yuki invites her on a trip to a hot spring. - The two set off on a graduation trip just for parents and children.