Season 03 Episode 02

Grantchester play Whittlesford at cricket. Sidney and Geordie bat together against everything the Whittlesford bowlers send down until Geordie notices Margaret Ward in the crowd, loses concentration and is bowled by a yorker. The visiting Pakistani batsman Zafar Ali then comes in, and the Grantchester captain, the solicitor Geoff Towler, sides with the fielding side over an LBW appeal that Zafar insists did not touch him. Rather than accept his own player's word, Geoff forfeits the match. Afterwards the cricketers and spectators eat and drink, and one by one they collapse, Geoff, Geordie and Sidney among them. It is arsenic, and Zafar dies of it.

Sidney is put to bed at the vicarage, where Amanda sits with him. Geordie learns that the beer, a vintage bitter Geoff buys from the brewery under a private arrangement, is the source. Zafar's brother Munir, who moved the body to a bath as a religious requirement and insists on burial before sunset, accuses Annie Towler. Annie admits she took Zafar tea that night but says she meant to tell her father about their relationship, and Sidney works out that Zafar intended to convert so that he could marry her. Bruises on Zafar's body show he had been beaten weeks earlier, in an attack Annie blames on her father.

Geoff tells Amanda that a divorce from Guy will need grounds, and that Guy will otherwise use her relationship with Sidney against her; he also tells her that she will be branded and that Grace's reputation will suffer. The archdeacon tells Sidney to distance himself from Amanda and instructs Leonard to make Amanda aware of it. Leonard, who has been courting Hilary Franklin at the archdeacon's prompting, goes to Amanda and makes the same case, and accepts that he and Amanda are in similar positions. Leonard unwittingly gives the poisoned beer to the dog, Dickens, who is taken to the vet, Neil Carver, and the medicine does not help. Munir throws a stone through the Towlers' window and calls Annie a murderer, then admits he had told her about the bride chosen for Zafar in Pakistan. Annie's room is found full of presents signed with the initials N.C., which she believed were from Neil. Neil denies sending them and proves the handwriting is not his. Annie runs away, tells Sidney she is pregnant, accuses her father of having Zafar beaten, and says he may have put something in his tea. Then Geordie finds a suicide note at the Towlers' and Geoff is taken to hospital, and the note reads like the fantasy novels that were on the family table.

Rosie Towler, Geoff's wife and Annie's mother, poisoned the beer with arsenic to kill Zafar, forged the gifts and the suicide note, and tried to make her husband's death look like the suicide of a guilty man. She had read romance novels and wanted a settled future for Annie as the wife of the vet. Dickens survived because the vet's own medicine was tampered with, which Sidney noticed when the medicine failed to work. Rosie is arrested and blames Neil for Annie's choices. At Zafar's memorial Sidney speaks about people living how they want to live and about the fantasy lives the others are leading. Geordie tells Margaret he will not come in and then does; Sidney goes to Amanda to end the relationship and finds she has decided the same thing, and their affair ends. The episode closes with Geordie in bed with Margaret, the affair continuing.

The episode is the one where the season's private business and its case are the same material, because a poisoned cricket tea, an engagement nobody agreed to and a forged suicide note all come out of a mother arranging her daughter's future without asking her. The cricket is the best opening of the run to this point, with a forfeited match over a racial appeal and the arsenic delivered in the drinks afterwards, and the dog surviving is the detail the episode hangs its solution on, since the medicine failing is what tells Sidney the tampering did not stop with the beer.