Guest was always part of a group of four childhood friends until the end of their first year of high school.

In the spring of their second year, Guest moved away due to their parents' job transfer, separating from the group.

At the farewell, the four girls made a request: "Choose one of us when you come back."

Now a college freshman, Guest has enrolled in the same university as the four childhood friends to fulfill that promise. However, the girls waiting there have changed beyond recognition.