Korosensei made a promise to Aguri Yukimura to look after her little sister since she'll be alone. But when he sensed that his time to disappear is near, he asked Nagisa and passed the promise onto him. An Assassination Classroom fanfiction, following the story that revolves around the two pig-tailed students after the series. (AN: This book was planned to be revised but author is on hiatus [which is me]. Will notify if I ever get back.)