Illyasviel is a normal girl living a normal life. But while taking a bath one night a strange magical stick enters her life and attempts to convince Illya to become a magical girl.
Illya has become a magical girl against her will but tries to go along with it anyway. Unfortunately, that means going out on her first mission without knowing how to use any of her magic.
A mysterious girl named Miyu appears and helps out Illya when she's in trouble. Things get weirder when this new girl transfers into Illya's class and moves into a house across the street.
Illya and Miyu must team up to take on Saber after being attacked suddenly. When Rin and Luvia are injured in the fight, it becomes apparent that Illya still hasn't mastered her magic.
After talking to her mother, Illya realizes what she should have done in the first place and goes to help Miyu take on the nearly invincible Berserker.