Aki and her husband divorced, and their son started living with his father. The day before the two left home, Aki, overcome by loneliness, had a relationship with her son Naoya. After that, the one day each year when she could see Naoya became Aki's reason for living. Eventually, Naoya's father remarried, and Aki was worried that her stepson might take Naoya away from her. The first time they met after Naoya got a stepmother had arrived…
