Matoi Sumeragi wishes for nothing more than to lead a normal life away from the spotlight. She is quite satisfied alternating between school and her part-time job at her best friend Yuma Kusanagi's family shrine. But this routine life is permanently disturbed when a Night—an evil extra-dimensional entity—attacks the shrine. Matoi is able to drive it off after unwittingly calling upon the powers of a god, the natural enemies of the Nights.

Matoi and Yuma are soon joined by Claris Tonitolus, an experienced exorcist from the Vatican, and agent Haruka Luciela, who works for the secretive Night defense organization IATO. Despite not knowing the perpetrator behind these attacks nor their motive, Matoi must come to master this newfound power in order to protect both the people around her and the once normal life she holds so dear.