A girl, Lisa Burrows, and her sister are walking along the river when the younger girl stops to tie her shoes. When she looks up, Lisa has disappeared.
John is at the birthday part of Frank's son and is forced to fill in when the hired clown doesn't show up. Frank realizes he's to blame when he didn't show the deposit check and his wife Tania blows up at him. John quickly improvises a costume and steps in to do balloon animals and magic. Frank and his wife are going to court to determine visitation issues and are clearly on edge. Frank is interrupted when he gets a call about the kidnapping case, and he and John head to the scene. They hear from a homeless woman who reports Lisa was taken and they find her jewelry nearby. When asked to identify the kidnapper, all the woman can say is, "Death."
Mr. Burrows is concerned and Frank tries to reassure him, telling Frank he has no idea what it is to have a child taken away. John diagnoses the witness Madeleine as having autism and concludes she's cuing off an olfactory memory of chloroform. They also find an oil patch corresponding to the time of the kidnapping, and figure it's a serial kidnapper since Lisa is the fourth abduction – there was a woman and two other children as well. Stella and Frank break down the oil sample and find traces of sulphur.
They go to a nearby sulphur plant and John spots an area that's disturbed. The police dig up the ground and find four skeletons – two children, an older woman, and a teenage girl. They take the bones back to the lab where Frank is clearly upset at the familial nature of the crime. Avery tells him to take some personal time and he reluctantly does so. He and John play basketball while Frank admits his concerns about how he's afraid of losing his children at the custody hearing the next day. John manages to cheer him up and they take off when it starts to rain.
Back at the lab, Nance determines the bodies aren't of the recent kidnap victims and John reconstructs the skulls to show the faces of the dead people. When he's done he concludes that they were all members of the same family. They identify the family as the Murchisons, who died in a car accident. They check the photos of the kidnapped victims and determine the dead family members are close in appearance to the victims. Only the father, Gary Murchison, is still alive and took possession of the bodies. And Gary lives close to the sulphur plant and his license number matches the numbers that Madeleine was rambling about at the crime scene.
They confront Murchison with a warrant but find nothing at the home. Murchison is obsessed with his coin collection and seems to believe his family is still alive. They determine he was at a psychiatric hospital and Frank takes him into custody. In interrogation, Murchison tries to pass off his confusion and Frank pushes him hard. When Frank starts hitting Murchison, Avery pulls him off. Checking his shopping records, they find that Murchison has been buying large amounts of food, but there's nothing at his house. Avery goes to interrogate Murchison but John figures he's a disassociate personality and she won't get anything out of him.
Later Frank shows up at John's apartment – someone took all of his stuff from his hotel room. He then notices that John has his mug and clothing – John snuck in and moved Frank's stuff to his apartment. John also has some advice on what Frank should say to the judge to get custody. Frank relents and agrees to stay as John's roommate.
The next day Frank asks to address the judge during the hearing and starts rattling off facts and figures provided by John. When that doesn't work so well, he makes a heartfelt appeal to make more time and be a better father. Avery has had no luck with Murchison and John comes up with an idea. Avery has Murchison transferred but en route a car slams into the police van and Murchison makes a break for it. As he leaves, John reveals he was the driver of the car and the whole thing is a setup.
Frank and John follow Murchison, with John providing his unique insight to find Murchison when he gives them the slip. They follow Murchison to a warehouse where he has the kidnapped victims locked up and pretends they're his "family." John and Frank find the concealed door and try to open it. Murchison hears them and starts filling his room with chloroform to kill himself and his family. John triggers the sprinkler system to disperse the chloroform and Murchison uses a mask to get a direct dose. Frank shorts out the electromagnet lock and they get in to save the kidnap victims but it's too late for Murchison.
After the kidnap victims are reunited with their family, John plays digger in foosball at The Sea and Frank reveals he got custody and he'll be moving out of John's apartment. Franks points that Digger loosened the goalie's seating screw. After making a long-winded story up, Digger runs for it with the others in hot pursuit.