Bokura no Koi wa Shi ni Itaru Yamai no You de

Akane’s childhood acquaintance with Aki leads to a promise of marriage from his younger twin, Sora, who says he will propose when she turns eighteen. Before that can happen, Sora dies in a traffic accident. After his death, someone appears before Akane with Sora’s voice, appearance, and every other detail just like him. It is Masaru, Aki’s younger twin, and Akane must face the complicated love and affection he directs toward her in place of Aki.