Yuto Kujo, a high school student, constantly compares himself to his exceptional older brother and sees himself as a lesser, "degraded version."

Caught in a spiral of self-deprecation, his adolescence turns even darker when he discovers that his childhood crush, Ryono, is in love with his older brother.

But just as Yuto begins to lose hope, Ryono's older sister, Natsuno—a college gal—develops intense, overwhelming feelings for him…!?