The final season kicks off in the momentous summer of 1963. Alphy reconnects with his estranged mother and questions his faith. Geordie faces a promotion that could end his crime-solving partnership with Alphy, and Cathy's career soars. As Leonard discovers his paternal side and Miss Scott faces a life-changing event, the Grantchester family must face love, loss, and forgiveness one last time. 

In season 10, as DI Geordie Keating and Reverend Alphy Kottaram continue to work together as a crime-solving duo in scenic Grantchester, they must also support each other through changing times, family struggles, and personal secrets. This season, Alphy feels like he's found a home, but he's forced to confront secrets he's kept close to his chest. Will he be able to let anyone fully in, or must he confront truths about himself first?

Season 9 begins in 1961, a period of accelerated social change throughout the UK. Will has begun to think of new possibilities outside the tiny village of Grantchester, and Geordie and Cathy are struggling to cope with the realities of Esme being out in the world. New drama enters the picture when Reverend Alphy arrives to a less-than-warm welcome.