Yori's conduct has undergone significant changes since their younger years. Despite being inseparable as twins, Yori has now taken to keeping himself away from his sister Iku. This has sparked concern in Iku, who believes that Yori no longer cares for her. However, the truth is scandalous. Yori has now become willing to risk it all in a pursuit of a romantic relationship with his younger sister. While Iku continues to hold her brother dear, Yori's desires have gone beyond the bounds of suitable sibling behavior. While Iku attempts to maintain their bond, Yori yearns for something beyond just familial ties. Will Iku eventually give in to Yori's advances and develop romantic inclinations for him?