Two decades after his apparent death, cult leader and serial killer Noah Cyrus appears on the doorstep of one of his followers. Against the clock, the team races to stop Cyrus' plans, but everything is not as it seems.

The team pursues Dr. Sidney Fairfax, a twisted neuroscientist who mutilates the brains of his victims; as the case unfolds, Bex realizes the doctor may have not only the key to larger mysteries surrounding the Pit, but insight into Shane's past.