Still Waters - S3.E7

Just as Paul Dangerfield has given up all hope of a romance with Liz, fate draws them back together when she joins the practice as a counsellor. It may seem a bit contrived, but there's no way Paul's ever going to find a girlfriend unless she's pushed right under his nose!

A romantic evening by the water ends in a suicide pact, but when the police recover the body of a young woman her lover's body has disappeared. The post mortem reveals the woman died before drowning and the murder enquiry focuses on two supposed wives associated with the missing man.