The legendary dollmaker Rozen created several unique dolls throughout his life, but it was not the materials he used that made them special. Known as Rozen Maidens, each doll was imbued with a Rosa Mystica—a precious gem that gives them life. But these dolls have a specific purpose: they must fight each other in a contest called the Alice Game. The winner becomes Alice, the perfect girl who will have the chance to meet their father and creator.

Jun Sakurada, a middle school shut-in, experiences the Alice Game up close and personal when one of these dolls arrives at his house. After winding her up with the spring provided, she comes to life and introduces herself as Shinku, the fifth Rozen Maiden. Despite Jun quickly becoming annoyed by her haughty attitude, they find themselves working together when they are attacked by another doll. At Shinku's behest, Jun becomes her medium, allowing her to use his life force as a power to defeat their enemies.

In the aftermath of the fight, more Rozen Maidens appear and decide to live at Jun's house. But can there be any peace when their very existence means they must fight each other?