Forensic psychologist Kristen Bouchard is hired by the Catholic Church to determine whether a serial killer is possessed by a demon or merely a psychopath.

Kristen, David and Ben investigate a supposed miracle when a teenage girl comes back to life after being declared dead for almost two hours; Kristen meets with her former boss and runs into Leland Townsend.

The team is sent to investigate the disappearance of a teenage boy, Wyatt.

The team is dispatched to a monastery to investigate the corpse of Father Thomas, whose body has not decayed in the year following his death.

David’s relationship with Kristen takes a turn when he gives into his temptation. Meanwhile, the team is tasked with exploring a machine to measure the weight of the human soul as it leaves a dying body.