Boku ga Otouto to Nakayoku Naru Houhou

During their childhood, siblings Haruki and Yuuki got along well despite being polar opposites. However, their bond has grown loose, as the two now barely talk to each other. One day, the siblings' mother decides to visit their grandmother, leaving them alone in the house. Long-haired Haruki uses this opportunity to regain their closeness and prepares dinner for his younger brother. While it may seem that the bespectacled Yuuki is disinterested in his older brother, he carries ulterior motives and an unexpected obsession, both of which Haruki is unaware of.