Loren Dean

After construction workers find the body of an archbishop whose kneecaps were surgically removed, the team is back on the case of the Widow's Son serial killer. When Angela discovers what appears to be a victim tree in the evidence vault, the team realizes the killer employs a systematic pattern in selecting victims. With a musician and an archbishop the first to go, the team tries to predict who might be next and how they can stop the killer before he strikes again. Brennan and Booth continue to see Dr. Lance Sweets (John Francis Daley), who has some helpful psychological insights into the Widow's Son's motives. Meanwhile, Brennan's brother, Russ, comes out of hiding when he finds out that his girlfriend's daughter is extremely sick, but his appearance causes Booth to intervene with Brennan's family once again.

While trying to determine the identity of a Jane Doe, Brennan is shocked to learn the remains are those of her mother, who went missing with her father 15 years ago. After years of uncertainty and not knowing what happened to her parents, Brennan finally has confirmation of her mother's death, and the news understandably hits her hard. Now that remains have been uncovered, Booth can open an investigation into the case for the first time. After researching Brennan's parents' lives, Booth surprises her with the news that her parents were not the people she thought they were - both were outlaws living under assumed identities. With the team working to glean more information from her mother's skeleton, to Brennan, she's now more of a Jane Doe than ever. As more details of her parents' past, in addition to her own, come to the surface, Brennan must come to grips with a whole new reality.

When a man’s body is found gutted, burned and hung up like a scarecrow on the roof of the Federal Building, Booth and Brennan are called in to identify the charred remains and determine who was behind the murder. Based on several factors, Booth determines the victim was a snitch working within an organized crime syndicate. Brennan’s brother, Russ (guest star Loren Dean), tells her he got a mysterious call from their long-lost father, warning him they are in danger, and Brennan is contacted by a priest (guest star Ryan O’Neal), who delivers a message from their father insisting she and Booth drop the case. Brennan and Booth determine the murdered victim was ex-FBI agent Garrett Delaney, who was tracking Russ and planning to kill him, giving more credence to their father’s warning. As more clues come to light and a government conspiracy is revealed, Booth and Brennan make a shocking discovery as to who was behind Delaney’s murder, and Booth is forced to make one of the most important decisions of his career, with very personal ramifications. Meanwhile, Zack must defend his dissertation, the last step to completing his doctorate, but needs some help from Angela to help him get taken seriously.

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.

Brennan's father, Max, is put on trial for the alleged murder of FBI Deputy Director Robert Kirby, and the entire Jeffersonian team, excluding Brennan, are called to be expert witnesses for the prosecution. As Booth and the rest of the team grapple with trying to be impartial knowing that their testimony could send Brennan's father to Death Row, Brennan insists that everyone participate objectively in the trial. With Brennan serving as a forensics advisor for the defense, she must rely not only on her expertise as an anthropologist but on her dedication to her family to find a way to exonerate her father.