Ty Panitz

Construction workers find a skeleton in an old fallout shelter from the 1950s and the Jeffersonian is brought in to help identify the remains. When Zack cuts into the bone, he accidentally releases spores of the deadly fungus Valley Fever, causing the team to be quarantined in the lab over Christmas. While everyone tries to maintain the holiday spirit, Brennan buckles down to solve the mystery of the fallout shelter.

Booth and Brennan examine the remains of a woman and fetus found in the Delaware Bay. The body is identified as that of Carlie Richardson, a pregnant newlywed whose mysterious disappearance one year ago had been a major national news story. Carlie’s husband Kyle Richardson is immediately thought to be the prime suspect in the case, but he disappears before Brennan and Booth can question him, prompting Booth to call for a manhunt for Kyle. Clues found with the remains throw suspicion in a different direction, and Brennan enlists Booth and her team at the Jeffersonian to recreate the potential scene of Carlie’s murder to get a better idea of the build and body type of the murderer, with shocking results. Meanwhile, Booth is annoyed that his ex-girlfriend Rachel, the mother of his son Parker, is letting Parker spend so much time with her new boyfriend, forcing Booth to be more territorial than Rachel would like.

Brennan and Booth are called to the scene of a deadly fire at a D.C. prison to investigate what they believe is the death of Brennan's incarcerated adversary, serial killer Howard Epps, whose body was found burned beyond recognition. But Brennan's examination leads to the chilling realization that the charred body is not Epps', but that of a D.C. fireman Epps killed in order to fake his own death and escape from a maximum security prison amid the commotion of the fire. After paying a visit to Epps' former wife, Caroline, to determine if she has any clue as to his whereabouts, Brennan and Booth leave empty-handed, but are concerned for Caroline's safety with her ex-husband on the loose. Their fears are quickly realized as they get concrete proof that Epps has killed again. As Epps leads Brennan and Booth into a game of cat and mouse, it's clear he is targeting them and the people they're close to, all the while giving them clues they desperately try to decipher before Epps takes another victim. While Cam conducts an autopsy on Epps' latest victim, Booth implores her to break protocol to save time and jump to a later step in the process. Against her better judgment she does, but she is sprayed with a deadly poison and critically injured. As Cam's life hangs in the balance, Booth, Brennan and the rest of the Jeffersonian team race to figure out what deadly substance is killing Cam and determine Epps' whereabouts before Cam becomes his latest victim.

The body of a man with a white beard and a tailor-made Santa costume is discovered in the sewer near a D.C. mall just three days before Christmas. As the team gathers forensic evidence, the victim seems to match the legend more closely each step of the way. Booth and Brennan discover the man, whose legal name was Kristopher Kringle, was a well respected Santa Claus impersonator, employed by a local "Rent-A-Santa" business. When Booth and Brennan inspect Kris' apartment, not only do they find his place decked out with holiday cheer, but they also find thousands of dollars stashed in a dresser drawer. As Christmas Day approaches, the Jeffersonian team works to find out who would have wanted this true-to-myth Santa dead. Meanwhile, Brennan visits her father in jail and plots a not-so-traditional Christmas reunion, and Booth and Brennan find themselves in close quarters with the mistletoe just overhead.

When Booth's son Parker finds a severed corpse finger in a bird's nest while playing with Booth, the team launches an investigation to find the rest of the body. They locate the corpse in Jefferson Memorial Park, and it soon becomes clear that the death was no accident. With the help of a new middle-aged grad student in the lab (guest star Michael Badalucco), the team identifies the victim as a local veterinarian whose penchant for gambling brings a number of suspects into the picture. When the victim's fatal injuries are found to be from a dog, the team uncovers an illegal dog fighting ring and enlists the help of Cesar Millan to help them connect the forensic canine evidence with the killer dog and its owner. Meanwhile, Booth asks Sweets to psychoanalyze his son who he thinks has been traumatized from finding the finger, and Sweets confronts Hodgins about his attitude in the lab.