- Writers: Chris Chibnall
- Stars: Adam Wilson , Andrew Buchan , Arthur Darvill , Benji Yapp , Carolyn Pickles , Charlotte Beaumont , Charlotte Rampling , David Tennant , Eve Myles , Hollie Burgess , James D'Arcy , Jodie Whittaker , Joe Sims , Jonathan Bailey , Marianne Jean-Baptiste , Matthew Gravelle , Meera Syal , Olivia Colman , Oskar McNamara , Pauline Quirke , Peter De Jersey , Phoebe Waller-Bridge , Simone McAullay , Steve Bennett , Susan Brown , Tanya Franks , Vicky McClure , Will Mellor , William Andrews
Hardy continues to irritate Ellie, especially when he gets her to sit in on Mark's interview. Mark explains his finger-prints were at the murder scene because he did some work there but key-holder Susan Wright denies letting him in and work-mate Nige destroys his alibi. However hotelier Becca Fisher comes forward to admit to an affair with Mark, thus giving him a new alibi. Following Steve's theory the police find that Mark does have a boat, stained with Danny's blood though Mark explains he cut himself on a fishing trip. Beth is approached by Steve, who tells her Danny was killed by somebody close to him, increasing her doubts about her husband. Meanwhile Karen, unable to get any locals to speak to her, tells Maggie and Olly she is gunning for Hardy after he failed to solve a similar case and Hardy tells his doctor he has taken on this investigation as a 'penance'. He does nonetheless accepts a dinner invitation with Ellie and her family.