High school student Yuito Kujou has always been compared to his brilliant older brother, leading him to constantly belittle himself as the "inferior version." To make matters worse, he discovers that his childhood crush, Suzuno, is in love with his brother, plunging his youth into a seemingly endless gloom. However, things take an unexpected turn when Suzuno's older sister, Natsuno—a flashy, gyaru university student—suddenly starts showering Yuito with intense, overwhelming feelings! What will become of this twisted tale of unrequited love and unexpected affection?