Kayano Saito, a shy high school student, attempts to confess her feelings to her crush and captain of the basketball team, Yuichi Kamijo.

[2] However, she accidentally gives her love letter to Takeru Edogawa, a rowdy first-year student and the principal's son, who ends up using it to blackmail her into following his orders.

In addition to their rivals, as Kayano and Takeru's parents' marriage looms closer and they begin living with each other, the two struggle with keeping their relationship a secret from them.

[7] An audio drama was released on CD by King Records on August 23, 2000, titled Dangerous Love Wars: The Devil Does Exist.

[9] A vomic (voice comic) adaptation was released on February 29, 2008, on Shueisha's website, S-Cast, to promote the bunkoban reprint of The Devil Does Exist.

[10] Publishers Weekly and AnimeLand [fr] praised The Devil Does Exist for its artwork and fashion, but both found the story neither complex nor distinctive.

[15][16] In addition, Publishers Weekly compared the story's premise to Hot Gimmick and described Kayano as "less a character" and "more a prize" towards her love interests.