The team are on the trail of a serial killer who is torturing and drowning women.The BAU are on their way to Sarasota, Florida, after hearing that a killer who has abducted, tortured and drowned four women is on the run with a fifth victim, Nicole Wagner.Mark Gregory (Andy Corneau, ‘Huff’) is aware that the police are on to him, which only makes him more dangerous: he feels like he has nothing to lose.“If he’s following his previous pattern, we have less than 12 hours to find Nicole Wagner alive,” says Gideon after the team split up to cover more ground.He and Reid will go to Gregory’s house to see what they can learn from it, while Elle and Hotch head off to interview Gregory’s friend and business partner, Hank Bloomberg, and Morgan brings Garcia up to speed on the situation.At Gregory’s spacious but sparse house, Gideon and Reid find evidence that Gregory is constantly reinventing himself, using catalogues for different types of uniform, various driving licences and all kinds of suits and watches.He has worked all over the country as a photographer and in real estate, and has a history of deviant behaviour including spying on women and statutory rape – as well as a failed 23-day marriage – behind him.But what is the root of the horror that compels him to ‘cleanse’ himself by drowning his victims?

When the news comes in that Nicole Wagner has been found dead in Georgia, it becomes clear that Gregory has moved out of the ‘safe’ environment that he knows and has now entered a random phase.

This means that it is much harder to predict what he’ll do next – and where he will do it.

And with his ability to gain women’s trust, Gregory has his pick of victims.

In an attempt to get some idea of what Gregory may be planning, Reid and Gideon talk to his father, Doug Gregory (Robert Pine, ‘CHiPS’).

Doug reveals that Mark’s mother was killed in a car accident when Mark was ten years old.

Could this traumatic incident have been what sparked Mark Gregory’s deviant behaviour towards women?

When the man weakly tries to explain away his son’s behaviour, Gideon berates him – having excuses made for him could be what let the boy develop into a killer.

When another woman is abducted, this time from Atlanta airport, security tapes show that Gregory snatched her after posing as a pilot.

Her body is later found in a run-down motel in South Carolina, and has been tortured and drowned.

Gregory has already disappeared into thin air and is known to be switching his licence plates as well as disguising himself.

How can the team find him when they are not sure what they looking for?

The investigation takes an intriguing turn when it is revealed that Gregory was injured in the accident that claimed his mother’s life.

Reid and Gideon go back to Gregory’s father to find out what else he has been hiding from them.

When it emerges that Mark’s first victim may actually have been his own mother, the team realise that his attacks are taking place near where the accident happened all those years ago.

However, he has already abducted his next victim... and is getting close to the water where his mother drowned.

Will the agents reach him before he manages to kill again?