JJ is boxing with her sparring partner in the gym when she has a memory flashback and loses control.
While in the locker room, she gets an IM notification from Garcia about a case. She gets another flashback about getting tortured, and smashes her locker in anger.
The new case is in Boulder City Nevada. Police found the frozen body of a woman wrapped and weighed down in the water. She has burn marks on her chest consistent with electric shock. The first assumption is that the unsub wants her to feel the pain of her death so he jolts her back awake with electric shocks. (JJ came to that conclusion based on her own experience with torture)
Carl Mason sits outside of a hardware store waiting for someone. Finally, a van pulls up and he is told to wear a hood on his head. Another man puts a zip-tie on his wrists and puts him in the van.
He is taken somewhere and put in a freezer as part of a ritual.
The dead frozen woman is Sarah Rhodes, of Kingman Arizona. She's a mother with a 10 year boy named Bobby. Her credit card and cell phone were canceled 3 years ago.
The team realizes that the electric shock marks on her body were consistent with resuscitation efforts.
Mason is removed from the freezer and is electro-shocked backed to consciousness, where a congregation and religious leader applaud him.
Reid and JJ interview one of Sarah's friends, who after telling her that there's an Amber Alert out on her son Bobby, lets them know that Bobby's father was never in the picture.
Reid explains that Sarah had been flooded with sugar and electrolytes but starved her of proteins - a common method to assist in brainwashing people. They have determined that she had joined a cult.
Garcia finds a frostbite victim who may have been another member of the cult. His name is Tom Fallon.
Reid confronts JJ about what's bothering her. She reveals to him that she was pregnant and had lost her baby girl during her ordeal with Tivon Askari. She swears him to secrecy.
Kate and Morgan visit Tom Morgan's mother Mary in order to interview her about her son. They discover that Tom is living there with her, and that they are both under strict orders from the cult not to defame their character under threat of legal action.
They interview Tom, who dismisses them as unenlightened.
Kate pretends to buy into his brainwashed consciousness in order to get him to tell them where the group is. He doesn't know, but refers to the cult as "The Forever People". He then reveals to them that he is missing all of his fingers.
One of the cultists named Adam Lewis fails the leader's strict test and is put into a freezer where he is frozen to death.
Garcia discovers that the cult is going under the name of the Global Warming Awareness Fund. From that name she is able to get the address of the cult.
Morgan and JJ go to the cult's address and take their leader Colton Gran into custody for questioning. Meanwhile JJ interviews cult member Carl Mason who reveals that the cult has his son Bobby. And that he pretending to be a cult believer in order to rescue him.
When interviewing Gran, Rossi and Hotch show him pictures of the two dead cultists. He invokes his right to remain silent, whereupon Rossi places him under arrest for murder.
After hearing Mason's explanation of his plan to rescue his son, JJ promises him to find the boy and get them both out.
Hotch and Rossi determine Gran didn't kill or sanction the kill of the cultists. Someone else has been killing them. They realize that the only suspect is the cultist named Jon who is watching the children.
Mason follows Jon out to where the kids are staying and he goes in to ask the kids where is son is. Jon sneaks up behind him and knocks him out with a baseball bat.
Reid and JJ storm into the compound and then search the trailer behind the place and discover Bobby and the other children.
JJ rushes to the Jon's house to rescue Mason. She suffers a flashback to her ordeal and ignores Hotch's order to wait for backup. She rushes in to a freezer where Mason is being held captive and near to freezing, while Jon is holding an acetylene torch . He warns JJ that the flash from her gun would kill them all but after getting him to admit the actual temperature, she realizes she can discharge her gun safely because the room is too cold for the gas to ignite. She shoots him dead.
The team bring Mason back to meet his son.
As they are leaving headquarters, Reid tells JJ he's asked Emily to provide some more background on Tivon Askari, which he has left in the office for JJ to read.
She learns that Askari has been raped and abused as a child, and then had turned to murdering people at the age of 13 for sexual pleasure. As she reads further, she imagines Askari speaking to her, telling her that he will continue to haunt her until she loses her job and her family.