Nicola Walker and Sanjeev Bhaskar return as detectives Cassie and Sunny, investigating another emotionally charged cold case. When the body of a teenage girl who went missing at the turn of the millennium is found at a building site off the M1, four old schoolfriends are placed under the spotlight and their relationships are tested to the limit. With Alex Jennings, Kevin R McNally, Neil Morrissey and James Fleet

S3 Ep1