Naval Petty Officer Lindsey Kirk awakes to find herself trapped in a room. Pride is packing for a fishing trip with his daughter. Martha Roberts, who Pride doesn't remember, says that Kirk has been kidnapped by a serial killer known as Mr. Lonesome. Sebastian recognizes her as a conspiracy enthusiast. She wants Pride to work with her on her case but he refuses. LaSalle and Gregorio discover Kirk was taken from her apartment. Martha tasers Pride to get him to help her and hauls him to her cabin. Martha said Mr. Lonesome showers his targets with gifts. The team visits an abandoned greenhouse and finds a newly built wall, with a dead body behind it. Pride gets loose and tries to text his team, but Martha has a signal jammer. Gregorio figures out there's a serial killer. The team decides that Pride is in trouble. They check video and determine that Martha had kidnapped Pride. The team finds Martha's cabin, just as Pride gets loose, again. But he's decided to work with Martha. Martha is obsessed because she sees the women as abandoned, just like her. They find that Brian Davis at the helpline call center is the only one who had contact with all the missing women and go after him, finding him playing piano at his home. Davis won't give the team any information, so Pride sends in Martha. Between them, they convince Davis to take them to LIndsey, who is still alive. Pride talks Martha into getting professional help. Pride heads out again to take his fishing trip.