The body of a missing computer expert turns up in a hospital morgue under a false name, so the team reopens the investigation into his disappearance. The dead man worked for the Metropolitan Police, giving him access to a great deal of sensitive information—added to which, he was in contact with a group of online hackers. As the seasoned detectives unravel the mystery, Brian struggles to accept Steve as the new UCOS member, forcing Esther to intervene.