Brennan and Booth walk the halls of a prison lead by Warden Everett to the cell where a major fire began. Inside the cell, Brennan inspects the body that was locked in. She's a little drowsy because the workman renovating the next-door apartment left a radio on all night, but she wakes up when the warden tells her that it is Howard Epps' cell. Brennan inspects Epps' burned body and finds that someone must have tossed accelerant on the body before they set it on fire, but when Brennan inspects Epps' wrist to check for the break that she had given him a year prior, she notes that this body has a freshly broken wrist. It's not Howard Epps. The Warden says that all prisoners have been accounted for, but Brennan cuts him off when she finds a DCFD tattoo and realizes that Epps must have killed a firefighter, stolen his clothes and mask, and walked out the front door.
At the lab, Zack, Angela, and Hodgins read an article about themselves that was published in the newspaper. It gives detailed bios on each of them and talks about the strong relationships they have in the workplace. Cam arrives and tells them to put the paper away and get her up to speed on what they found on the dead firefighters body. Hodgins says the accelerant was distilled alcohol and Zack confirms that the wrist was a fresh break.
In Brennan's office B&B sits with Epps' ex-wife Caroline Epps. She explains that she is no longer in contact with Howard. She explains that she's moved on and wants nothing to do with Howard or this investigation. She leaves and Brennan worries about her safety, meanwhile Booth is worried about Brennan's security. He doubles up security at the lab incase Epps comes after anyone. Then Brennan gets a phone call from Epps himself. He tells her that everything he does from this point on is her fault. He also tells her to "use her head." Brennan takes this as a clue. Booth has traced the call and they go to the pay phone he was using to find a small vile of bone dust.
At the lab, Brennan, Zack and Hodgins inspect the bone dust. Zack says that it comes from someone in their mid 30's, but he can't tell what sex. Hodgins find common spices mixed in with the bones dust and Brennan reminds them that Epps like to leave clues. Then they hear a scream from across the lab.They dash into Angela's office to find her starring at a package. Inside the package is a human heart. Also inside the box is a cut out from the article written about them in the newspaper.
Brennan and Cam inspect the heart and Hodgins cones in to tell them that the spices found are all commonly used to make curry for Indian food. Booth remembers that Epps ex-wife used to live over an Indian food restaurant.At Caroline Epps' apartment, Booth and Brennan open the door to find her empty apartment. The only thing left is the refrigerator. Booth opens the fridge to find Caroline Epps' head, frozen solid.
At the lab, the gang checks out Caroline's head. Cam notes that there is some sort of white powder in her hair. With further inspection Cam finds that Caroline was alive when Epps cut her head off. Booth wants to get t his guy NOW and decides that they should bring in his mother. His profile says that he's attached to her and that her parental behavior may have lead to his behavior.
With Marriane Epps, B&B find out that she would bath him in ammonia after he went on dates with girls. She tried to raise a son of the Good Book. She's clearly disturbed herself.
En route, B&B discuss Mrs. Epps and her mental wellbeing. Cam calls and tells them that she found a token in Caroline Epps' skull from the same park that Booth's son Parker plays at. Booth steps on it, to the park.They arrive at the park and search for Booth's son. They find him eating ice cream that was bought for him by a strange man. They toss the ice cream, but find a clue on the napkin. It reads, "My name is Parker. Ask me how I can solve this case." Parker doesn't have any info for them.
Back at the lab, Cam has just heard about Booth's son and decides to skip protocol, not X-ray, and just cut into Caroline's skull for evidence. As she cuts, a powder shoots out of the skull and into her face. It's a booby-trap set by Epps and Cam's inhaled it. Zack hit the alarm and throws on a mask, but it's too late for Cam. She hits the ground convulsing.
At the hospital, B&B visit Cam who is unconscious and fluid is building in her lungs. Hodgins arrives with Cam's clothing in a haz-mat bag and intends to find out what the poisonous powder is.
At the lab Hodgins search isn't going well. He hasn't found any powder on her clothes. He goes to Caroline's head in search of particles.Cam wakes up and Booth consoles her.Brennan sits in her office trying to piece things together and gets a call from Epps and when Brennan reveals that Cam was poisoned and she asks for the remedy, Epps utters, "The body know what the head can't say." Then Brennan throws him off by saying that they've detained his mother. This throws him. It's twice as personal now.
In the lab, Hodgins is striking out and Zack can't help him. Booth arrives to get an update and is furious that the squints haven't done their job. Booth asks them what they have found and they say components found in common drywall and leather goods. With the Parker clue from earlier Zack finds a Parker & Parker Leather Goods shop on Parker street in the near by town of Parker. Good enough for him. He grabs Zack and Brennan and they head out.Outside Parker & Parker, B&B gets ready to head in with FBI SWAT and Zack. Inside they find a woman's body. On the body sits a bag of the poison used to get Cam. When Zack grabs for it he triggers a bomb. Booth tells him to hold and tells everyone else to clear out. Booth preps Zack and tips a table over to duck behind. When Zack removes his hand from the body Booth yanks him behind the table and the bomb explodes.
At the lab, the gang watches the news reporting that Brennan, Booth and Zack were injured in the blast, which isn't true because they're all sitting right there with Hodgins as he racks his brain and finds the chemical used on Cam. He phones the hospital and they start the correct treatment. Booth tells Brennan to go home because he's calling it a day and going to be with Cam at the hospital.
At the hospital, Cam wakes up feeling better, but far from well and Booth is glad she'll be OK. She jokingly says she feels like she inhaled plaster dust. Booth thinks, "Plaster dust," and runs out the door.At Brennan's apartment, FBI agents check out her place and then wait outside. While Brennan's shower runs, Epps exits from her closet and we see that he's cut through the wall from the next-door apartment that was having renovations. Booth enters quietly from the front door and Brennan steps out of the bathroom, still clothed and pulls her gun out on Epps. Booth follows up and they have him trapped. He tries to flee and jump off the balcony, but Booth grabs him. Booth tries to pull him up, but can't. Epps falls to his death.