I Kissed My Girlfriend's Little Sister

In the Japanese light novel Kanojo no Imouto to Kiss wo shita, readers are introduced to Hiromichi Sato, who faces an unexpected twist in his relationship with his girlfriend, Haruka, when his parents decide to remarry, bringing a new step-sister into his life who bears a striking resemblance to Haruka. This romantic comedy explores themes of siblings not related by blood, forced into a relationship, and yandere tendencies, amidst an apartment life setting. With elements of blackmail, love triangles, and a perverted protagonist, the story offers a mix of humor and ecchi moments, making it an engaging read for fans of romance and slice of life genres.