Rozen Maiden

Jun Sakurada, a middle school shut-in refuses to go to school after being traumatized by an embarrassing incident at school. One day, he receives a letter asking "yes or no", and chose "yes", meeting the living doll Shinku and the events of the original Rozen Maiden series unfolding. However, what would have happened if he had chosen "no"? Although he overcame his shut-in nature, this Jun can't find a place where he belongs. (myanimelist.net)