Mokka, Mimodaeshi Mune no Uchi.
目下、身悶えし胸の内。
Gen is found lying bruised and bloodied on the sidewalk by Kiba, who takes him in. The two quickly become friends, forming a bond that seems to offer Gen a new start. However, Gen's life takes a complicated turn when he discovers that the girl he is sleeping with is Kiba's ex-girlfriend.
As Gen learns more about Kiba's past relationships, he becomes increasingly obsessed with hearing about his friend's romantic exploits. This fascination drives Gen to pursue more of Kiba's "leftovers," blurring the lines between friendship and a darker fixation. The story explores the twisted dynamics that develop as Gen's obsession grows.