(gentle music) - Yes, you're back with us as of this morning of course.

- Yes sir.

- [Bright] Splendid.

- What you got today then?

- Unbelievable writer Russell.

He must have had a vision, an arc for each character, where he wants them all to develop to and end up and potentially go on from, a phenomenal canvas of characters.

Phenomenal reference library in his head of times and films and fashions and political landscapes and contexts.

Amazing, I just am blown away by his skill and you can sense a real love for the whole Morse legacy and for all the characters.

- What Russell and Damien Timmer and Mammoth Screen have done is managed to capture the magic of that, the quality of the storytelling, Colin Dexter's beautiful work and the intricacies of all of those puzzling dramas and bring it, albeit through the lens of the sixties and seventies, in a very modern noir, beautiful cinematic way.

And that's where I think the charm is really for a show like "Endeavour".

And why indeed it's run for nine series now.

- Small wonder really the way they chop and change the lines on this, it's a miracle I can keep anything in my head at all.

(laughing) - More than ever, fans will be looking for those Easter eggs and Russell is delivering in spades.

We will have the very obvious ones where somebody walks onto screen and we realize that is harking back to a former story.

And it goes all the way down to the score that Matt Slater will be writing where we are picking up on little sound cues that we will have heard previously or allude into things we've heard previously.

The beauty of Russell's writing for me is when I'm given that very first draft script and I go through it and I think, there's this, there's that, there's this from series one, from series two, oh and there's this from 1971.

And I go through that script and I feel very pleased with myself that I've picked up on all these beautiful Easter eggs and then someone else will read it and say, oh, did you catch this from series five?

And did you catch that from the Rolling Stones?

'Cause that song was released in the year that we're setting this show.

And I'll think, gosh, I've missed so many.

For me, it is in the breath of references.

- Jesus.

- Yes, Sergeant.

I'd rather think that was the general idea.

- It means any viewer that watches, be it somebody who saw all of Morse in the nineties and continues to watch Endeavor now, or if it's someone who watches online through streamers and comes across Endeavour much, much younger, they too will be able to pick up on lots of beautiful texture.