Former FBI agent, Ryan Hardy is called out of retirement to track down Joe Carroll after he escapes from prison. Hardy works closely with an FBI team, which includes young, razor-sharp Mike Weston. The investigation also leads Hardy back to Claire Matthews, Carroll's ex-wife and the mother of the criminal's young son, Joey. Hardy soon discovers that Carroll has an ever-growing cult of followers.

Ryan Hardy, Agent Mike Weston and FBI Specialist Debra Parker, who is brought in to lead the investigation into Joe Carroll and his followers, dive deeper into the history of Carroll's psyche. To do so, they enlist the help of Carroll's ex-wife, and Hardy's former love, Claire Matthews. Meanwhile, Emma, Jacob and Paul keep Claire's son Joey at a house in the country as they prepare for their next move

After discovering Claire's location, Joe sends two followers to capture her, but Ryan may be one step ahead. Meanwhile, Jacob struggles with recent decisions causing his reunion with Emma to be less than ideal. Also, a relationship from Ryan's past plays a significant role in his future.

After losing Claire to Joe's followers, Ryan and Parker attempt to recover while the FBI tracks down an undercover location that may have dark ties to Joe's following. Meanwhile, Claire adjusts to life at the follower's mansion and has an unexpected reunion, while Emma and Jacob continue to deal with Emma's betrayal.

In the explosive Season One finale, Ryan races to stop Joe Carroll before his endgame reaches a deadly conclusion. Meanwhile, Joe leads Claire to a special location and the ultimate showdown between good and evil takes place.

One year after Ryan Hardy's pursuit of serial killer Joe Carroll, a healthy and healed Ryan is living in New York City. On the surface, it appears Ryan's gotten his life back together. But deep down, his obsession with Joe continues to grow. Then, on the anniversary of Joe's death, a new murderous rampage leaves everyone shocked and determined to discover the truth.

Mark and Luke turn the tables on both Ryan Hardy and Joe Carroll, forcing the two sworn enemies to come together to save the woman they love.