When a life-threatening accident renders sixteen-year-old Ronnie Hendrix comatose, he dreams of his hometown in flames and a giant axe at the center of it. After he recovers, Ronnie, sick and tired of being bullied, begins writing in a notebook, detailing the ritualistic deaths of those responsible for his accident. In the notebook, their sacrifices lead to the ceremonial summoning of Karnalaxe, a demon large enough to wield the weapon from his nightmare.

Ronnie finds his revenge on the page, never intending to hurt the bullies himself. But soon after he returns to school, the notebook is stolen.

The following day, one of the bullies is found dead in the same manner described in the notebook. Afraid that he will be framed for the murder, Ronnie tries desperately to uncover who's behind it, until the Neverwells, a masked cult with mind-altering abilities, take credit for the murder on social media, believing they can summon Karnalaxe by following Ronnie's plan.

With the help of his punk rocker best friend, a jock, and a powerful young witch, Ronnie races to stop the remaining rituals while uncovering the secrets of his birthright. The journey leads Ronnie to his estranged father, who might be his only chance at stopping the Neverwells for good.