Episode 4x13 - The Double Trouble in the Panhandle
The team investigates the death of female conjoined twins who were in the process of deciding to get separated or not. The twins were working in a circus, which means that Booth will come face to face with a clown during the investigation. Brennan and Booth go undercover as Wanda and Buck Moosejaw, Canadian performers in a knife-throwing act. Sweets helps Brennan and Booth understand Circus lingo. Angela, Hodgins, Cam and Vincent Nigel-Murray appear.
Episode 4x14 - The Fire in the Ice
The body of a fireman is discovered in a lake and Booth is one of the suspects. The victim and Booth played hockey together. The investigation is conducted by FBI Agent Payton Perotta. During interrogation, sparks fly between Perotta and Booth. Brennan will try figure skating. Cam, Hodgins, Wendell and Sweets also appears.
Episode 4x15 - The Hero in the Hold
Hodgins is not over when he and Brennan got taken hostage a while back. He may even be partially to blame for Booth's kidnapping. Turns out Booth was tasered, knocked out and stuffed in a toy-like yellow submarine. When he gets out of the tiny submarine, Booth finds himself face to face with someone from his military past. The team works on locating Booth and finding who is behind the kidnapping. We learn why Booth's son is named Parker. Brennan, Hodgins and Thomas Vega, from episode 2.09, face Judge Dix Williams and AUSA Kim Kurland, also from episode 2.09, and learn that evidence in the Grave Digger's case has gone missing. The three of them are suspected of taking the evidence. Hodgins is obsessed by the Grave Digger and Vega is writing a book on the subject. Angela, Sweets, Cam, Agent Perotta and Jared also appear.