Season 01 Episode 06

Amanda and Guy are to be married at the end of the week. Sidney is drinking, cannot sleep and has told nobody that marrying them is destroying him. A police officer is shot dead outside the station and Geordie takes the case. Sidney, who is known to the women who work the street nearby, is taken to one of them, Annie, who will speak only to him: she heard the gunman say a word, which turns out to be Merlin, the name of the factory on the edge of the village. At the factory the caretaker, Thomas Langshaw, is dead in the same way as the officer, and Geordie, searching the buildings, is shot in the stomach. Before he goes into surgery he says one word to Sidney, heart. Cathy Keating and the children wait for news.

Chief Inspector Benson takes over the case and shuts Sidney out. Mrs Maguire and Leonard create a diversion at the station so that Sidney can look through Geordie's office, and DC Atkins sees him and lets him go. Sidney learns that the dead officer's funeral is being paid for by James Heath, his old commanding officer, and that the dead man was one of Heath's men in the war. Heath denies everything and offers to help, and his wife Grace gives Sidney the list of Heath's men and he sees the bruises on her arms, which she explains away.

Another of the list, Robert Miller, tells Sidney what happened at Spreenhagen outside Berlin: that German prisoners who had surrendered were shot, that Miller had refused and had been called a coward for it, and that Heath did it and has been killing the men who could say so. Sidney takes the account at face value until the word Geordie said in the operating theatre gives the game away. Miller carried the killings out himself, and the photograph and his tattoo expose him. Sidney confronts him, the two fight, and Miller holds him at gunpoint and then shoots himself as the police arrive.

Geordie recovers, and Cathy brings him home. Sidney finally tells Geordie the thing he has never told anyone: in the war he gave the all-clear at a position where he had missed a German soldier, the soldier shot his friend Sandy, and Sidney shot Sandy himself to end his pain. That is the flashback the series has returned to since the first episode, and it is the reason he has never been able to forgive himself. Hildegard ends their engagement after Mrs Maguire tells her about Gloria Dee, and she leaves Grantchester for Berlin, though the last shot of her shows her being greeted in the street by a man who appears to know her. Sidney tells Amanda he will not take the wedding, and they say goodbye at the National Gallery in London.

The finale is the point at which the series pays off everything it has withheld, because the war material that has run through the first five episodes turns out to be the case rather than the background. The structure is unusual, with the detective shot early and the investigation run by a vicar who has no standing at all, and the resolution depends on a single word spoken by a wounded man before surgery. Sidney's confession to Geordie is the scene the whole first series has been moving towards, and it arrives after the killer has already shot himself rather than before.