Navy pilot Sophie Kendrick is tortured, then smothered, in a remote farmhouse. Gregorio remembers a similar case from her FBI training days. Gregorio calls Claire McDermott, her former behavioral-science teacher. Pride agrees with Sebastian that Gregorio seems a bit off. Gregorio found 10 similar murders over the past decade from all around the country. McDermott breaks into Gregorio's apartment and is there while Gregorio is talking to her on the phone. Gregorio spies someone in her apartment, but no one is there when she arrives. Gregorio has figured out McDermott is the killer. Pride has Gregorio work from home, with Sebastian there  as backup. Loretta determines that all the victims were drugged, then tortured with the same scalpel. McDermott drugs and abducts Brooklyn. McDermott calls Gregorio on Brooklyn's phone, and tells Gregorio to shake Sebastian and drive away, or she would kill Brooklyn. Pride suggests profiling Gregorio, to figure out where McDermott would take her. McDermott makes Gregorio toss out her phone. Gregorio runs a stop light so it takes a photo of her as a clue for the team. McDermott has Brooklyn in the trunk. McDermott wants Gregorio to remember a day in her past in Hawaii. Pride and LaSalle find Brooklyn, who McDermott left at Gregorio's car. McDermott took Gregorio to the Aloha Motel. Pride determines that McDermott wants the victims to admit what they did. Gregorio confronts McDermott about killing her father, and McDermott smashes her fingers with a hammer. The team finds a scrapbook about her trip to Hawaii during which Gregorio's friend Andrea was killed. Gregorio blamed herself for not telling Andrea's parents when Andrea stepped out. McDermott put a bag over Gregorio's head. Gregorio gets one bloody hand loose and wallops McDermott with a chair, but Pride stops her before she kills McDermott.