The team investigates the case of a husband-and-wife serial killer team, Jacob and Sarah Jean Dawes, who have been convicted of murdering 13 young blonde girls in 1985. The couple is on death row at the Florida State Prison.
Jacob and Sarah Jean are scheduled to be executed within 35 hours. Sarah Jean has confessed to the murder of her son, Riley. The BAU is called because several other victims, mostly girls and women, have not been identified. Thus, the team hopes to solve the cases either with or without the killers help. Elle and Morgan investigate the home of for clues. They find a storage shed that Jacob used to torture his victims. They then speak with Deb Mason, Sarah Jean's mother, hoping to get an overview of her family life. Mrs. Mason sheds light concerning Jacob and Sarah Jean by telling them he was a control freak and an abusive husband.
Gideon talks to the warden of the prison, Charles Diehl, who offers few clues. After meeting Sarah Jean for the first time, Gideon sees she is a very intelligent woman with keepsakes, such as paintings, in her cell.
Hotch interviews Jacob, who stalls and plays games during the interrogation. By his own admission, Jacob is a diagnosed sexual psychopath.
A breakthrough is made in the case when Elle finds a letter from Sarah Jean to her mother that reads as "a statement of innocence." Apparently, Sarah Jean did not murder her son. The team must now find evidence to clear her of all wrongdoing before she is executed. Sarah Jean does not help matters by remaining adamant that she is just as guilty as her husband because she knew he was committing the murders. The team doesn't believe her story and thinks she is admitting out of guilt of what happened to the other victims.
Reid provides a more extensive profile of the case. Since Jacob is a diagnosed psychopath, it would be a fair conclusion that Sarah Jean, regardless of whether she knew about the killings or didn't know, was an unwilling participant. However, the appeals attorney wants actual evidence that clears Sarah Jean. Hotch returns to the prison to interview Jacob, who still wants to play cards. Because Jacob prefers young girls, JJ volunteers to go in and has changed her hairstyle to look like his preferred victims. Jacob offers to play a card game. If Hotchner wins, Jacob tells him everything. If Jacob wins, he gets to smell JJ's hair. JJ agrees to the rule.
Meanwhile, Gideon attempts to get Sarah Jean to open up about Riley and admit her innocence.
Hotchner wins the card game, and Jacob gives him the location of a 14th victim.
During the last hours, Sarah Jean continues to stall. Gideon devises a plan to have Sarah Jean removed from her cell with the warden so he can search for any info on Riley. He finds a picture of Riley hidden inside of one of her paintings. He is not dead.
Gideon asks Garcia, Morgan and Hotch to track down any adoption agencies to see who would match Riley's profile. Garcia finds a current picture of Riley. Morgan and Elle head to the location of Riley's adoptive parents.
Hotchner comes in to witness Jacob's execution and throws it in his face that he didn't kill Riley. Jacob is executed knowing he didn't kill his son because Sarah Jean hidden him all this time. However, Sarah Jean still refuses to cooperate. When Morgan and Elle arrive at the adoptive parents' house, Sarah Jean tells Gideon not to tell Riley that his mother is alive. She tells him he is better off not knowing who his real parents are. In her own words, she is protecting Riley up to the very end, including the unnecessary execution.
Gideon tells Morgan and Elle not to tell Riley about his birth mother. Gideon visits Riley, who is an expert musician, at a concert.