Noticing his car is causing him grief, Piper prompts Cassius to take it in to the garage and Mark lets Bea take the lead on fixing it. After replacing the gearbox, Bea gives the car a clean and finds a key ring with a distinctive motif engraved on one side which happens to be the same emblem on the medallion Cassius lost the night he murdered Hamish. When Cassius comes to collect his car at ... (thetvdb.com)