This episode takes us to Bristol, where police launch a major missing persons enquiry following the disappearance of 25-year-old Jo Yeates. Days later, the body of the young woman is discovered by dog walkers on Christmas Day, and immediately the case becomes a murder enquiry. As investigators find no sign of forced entry into Jo's flat, they conclude the killer must be someone known to her. Detectives initially hope DNA samples would lead them to her killer, but when the evidence doesn't reveal any further leads, they turn to Dr Kelly Sheridan, an expert in fibre analysis. By inspecting Jo's clothes and fibres found in her flat, Kelly's evidence is crucial in identifying and convicting the killer. With interviews from Dr Sheridan and news reporter Ronke Phillips. In Wolverhampton, teenage sex worker Marcella Davies is reported missing after failing to collect her baby from her childminder. Tireless police work eventually uncovers a suspect, but without finding Marcella's remains, the likelihood of conviction is low. Police turn to forensic archaeologist Professor John Hunter to search and excavate potential deposition sites, including a wood yard the suspect had access to. Alongside colleague and archaeozoologist Umberto Albarella, John and the team make discoveries, including bone fragments and teeth, that can be linked back to Marcella. Their work not only returns Marcella to loved ones but convicts a dangerous killer.