S2, E18: A partial skeleton is found encased in cement, and Brennan, Booth and the Jeffersonian team are called in to investigate. Booth suspects the victim was killed by Hugh Kennedy, a member of a dangerous organized crime family. Complicating his plan to find and arrest Kennedy is the claim by a bounty hunter that she saw Kennedy burn to death in a car explosion, but the facts don't add up for Booth, and he tries to lure him out of hiding. But when Booth goes after Kennedy, the plan doesn't go as he envisioned and Kennedy kidnaps Booth, leaving Brennan to try to find Booth before he suffers the same fate as the original victim. Meanwhile, visiting her mother's grave, Brennan is paid a surprise visit by her father Max (guest star Ryan O'Neal), who attempts to get her to listen to what he has to say about her deceased mother. Brennan is not willing to indulge her criminal father and does not hesitate to call the police, but Max is gone before they arrive. Max shows up again at her apartment, and still can't get her to listen to him before calling the police, but Brennan's reactions let Max knows he may be starting to get through to his daughter. After Booth disappears, Brennan turns to her father, who has extensive experience in avoiding the law, for help in finding Booth. As Booth's life and the life of his son are threatened for information he has on the case, Brennan and her father make an unlikely team who race to find Booth before it's too late.