Ten years ago, Kiriko divorced and devoted herself to raising her son Masaki alone, eventually inheriting her parents' estate to support their life. Using that money, she successfully opened a Japanese restaurant overseas and moved to London, leaving Masaki behind. When Kiriko finally returns home for a rare vacation, Masaki goes to the airport to pick her up. Looking forward to their long-overdue reunion, the two plan to spend some quiet, relaxing time together at a hot spring resort.