Imouto

Yosugara Hikaru and his young sister, Mioto, share a bond with their childhood friends, Sugihara Hakurou and his sister, Akimi. Despite Mioto's deep affection for Hakurou, Hikaru harbors a concealed love for her. One fateful day, Akimi intrudes on Hikaru in his room while he indulges in an intimate act, having spied on Mioto and Hakurou. Demanding retribution, Akimi coerces Hikaru into finding a way to separate the siblings, as she too is enamored with her brother. Initially resisting, Hikaru capitulates after Akimi threatens exposure of his transgression. Consumed by guilt, Hikaru begrudgingly agrees to collaborate with Akimi on one condition: the secrecy of his reprehensible actions must be preserved.