Tsugumi Dozono works at a large electronics company in Tokyo. She likes to spend long vacations at her grandmother’s house in the countryside. When her grandmother dies, Tsugumi Dozono decides to live in the house full-time, and to work from there as well. However, one day she encounters a middle-aged man in the house, who tells Tsugumi that her grandmother gave him a key to the annex house when he was her student. The two share the property, although Tsugumi still does not know the exact relationship that her grandmother had with this man.