A group of teenagers are driving when a skull smashes through the windshield. Brennan tests a young forensic anthropologist as a replacement for Zack, while she and Cam inspect the skull. The find human teeth marks on the skull, suggesting that cannibalism may have been involved. Once the victim is identified, Booth and Brennan head out into the field and clues lead them to a cannibalistic society. Meanwhile, Cam suggests hiring a private investigator so Angela can track down her ex-husband, but that proves to be easier said than done.