Bentley Grimes is a killer not content with just taking a victim's life, he also wants to experience emotions. When he kills George Braddock, Bentley infiltrates the Braddock household by befriending his victim's oldest daughter, Katie. He witnesses their misery searching for that indefinable trait that makes him different from the rest of the world. Frank Miles is a detective with his own demons, and his own obsession, catching George Braddock's murderer. The three, Katie, Frank and Bentley are all on a collision course for each other, none of them knowing the secrets that each hides in their souls.

The sequel to Beneath the Mask of Sanity, Beyond the Mask begins ten years after Bentley's murders. Bentley is being released from the mental institution and almost immediately the murders begin again. Sheriff Frank Miles is in the unfortunate position of Bentley's alias (Bentley was with him during the first murder) and knows Bentley didn't commit the crime. When Bentley asks to lend his unique insight to the case, Frank is hesitant. Yet, he knows that he would work with the Devil himself to solve a crime. Bentley and Frank follow the killer's trail, trying to keep up before they are the next victims.

Before Bentley Grimes was a vicious killer, he was just a normal high school student. Well...not exactly normal. When a new student named Monica meets Bentley she is instantly drawn to him. Does Bentley feel the same way? What could this mean for his murderous plans? Can anyone survive what he wishes to become?