(upbeat music) - [Rishi] Season 11!

- Season 11.

But it's not just season 11, it's the final ever season of "Grantchester."

- Ever, ever, ever.

(Robson sobs) - We joked about this, and we'd say, you know, "Imagine if this gets to season 10 or 11."

Geordie will still be there wearing the same costume and have gray hair.

So what happens to Alphy in season 11?

- [Rishi] Things are going really well.

He's very hopeful.

- Alphy, hello again.

(gentle music) - We left him at the end of season 10, knocking on his mother's door.

Pick up in season 11, time has passed.

- A big day coming up.

- Ah, it's not that big.

- You must be nervous.

- I'm excited.

- Your mother's first visit, she'll be so proud, - So exciting.

Best behavior, I promise.

- And then it kind of all goes a bit pear shaped and it doesn't quite work out as he wants.

- You are worried it's all going to fall apart.

But here's the thing, what if it doesn't?

- Series 11 is about, what is family?

- It's a strange thing when you know it's the end.

But it's sort of a liberating thing.

(upbeat music) - Sit back, relax, enjoy.

(people clapping) - This year we have a drive-in movie, so we had all like, the Cadillacs and all the old American cars.

- Hey, stop, stop!

(brakes squeal) - Cue the investigation.

- A crime wave is sweeping Grantchester.

- This shall not stand, Mrs.

C.

- Things start going missing in the village.

And Mrs.

C and Leonard hatch a plan to catch the criminal.

- And that was great fun 'cause that was like the old days where they were a bit of a double act.

- We're now in 1963.

Cathy is loving it, enjoying the fashion.

It's really good fun.

- And for Geordie, is it time for him to pass on the baton?

- You're a detective inspector in the making.

- It's surreal and it's brilliant that we get to have these journeys.

- Hand on heart, it's the best season yet.

- It is.

(upbeat '60s rock n roll music)