After reaching a dead end in the search for Jason's killer, Helen has to fight for her own life, while Sam receives a threat from his former employer.

Cast: Keira Knightley, Ben Whishaw, Sarah Lancashire, Andrew Buchan, Andrew Koji, Omari Douglas, Kathryn Hunter, Sam Troughton, Ella Lily Hyland, Gabrielle Creevy, Isabella Wei, Molly Chesworth, Ken Nwosu, Paapa Essiedu, Charlotte Rice-Foley, Taylor Sullivan, Julian Wadham, Luther Ford