In the special two-hour season premiere: It’s 1956 in Grantchester, and the post-war rulebook is being torn up – it’s the birth of the teenager, the era of Elvis. There’s change at the vicarage, too. Reverend Sidney Chambers is feeling adrift. He needs a little danger in his life, which is exactly what he gets when American civil rights activist Violet Todd arrives in the city and fires up his need for social justice. And soon enough, there’s a new Vicar of Grantchester: firebrand Will Davenport.

Sidney is swept up in the civil rights movement when Reverend Todd and his daughter arrive – and a murder sees racial tensions spike. Sidney struggles to remember a victim’s final words. Geordie investigates a slum connected to a deadly web of vice.