The first episode of the BBC's six-part mini-series introduces us to Detective Inspector John River (Stellan Skarsgård). Already known as a bit of an odd duck by his coworkers, River is in further distress by the recent murder of his partner Stevie (Nicola Walker) who continues to appear to him (and whom he talks to as if she was still alive). Despite his amazing ability to close cases, River's erratic behavior has led to mandatory counseling with a department psychiatrist (Georgina Rich) and raised questions about his fitness as a police officer.
There are two cases concerning River in the series' opening episode. The first is the unsolved murder of his partner. Noticing a car matching the one which ran her over, River chases a suspect who falls to his death while fleeing from the officer. Despite forensic evidence that ties the car to the murder, River is less than certain that their dead suspect is their killer. The second storyline involves a man who has confessed to killing his girlfriend (Shannon Tarbet) but refuses to disclose the location of her body. As with his partner, the girl appears to River throughout the episode, sometimes helpful and sometimes not, but River's inability to believe the prisoner's confession eventually helps him to discover what really happened.
River offers an intriguing setup. The detective isn't haunted in the traditional sense. These are manifestations, not apparitions. He's fully aware that the people he's speaking to aren't there, yet his ability to interact helps him both emotionally to deal with the circumstances of the crimes which took their lives and intellectually to help solve those same crimes. These individuals don't answer questions directly, but they do push his mind in new directions to help him solve his cases.