Ootori Aisu is a daughter of the wealthy Ootori family. Her father has started putting pressure on her to get engaged to a suitable guy, but she already has her sights set on someone else named Hiro, whom she met through her childhood friend, Ren. Angry at her dad, she runs away from home and asks to stay at Ren's house during their summer vacation. He grudgingly agrees, but seems to be hiding something. Aisu finds out soon thereafter that Ren, Hiro, and Yuuto, the three most desirable guys at her school were crashing at Ren's house to work on a big project. What will happen to the four of them this summer?