Now, a very famous TV detective comes back to our screens this weekend. You may have heard of him: Inspector Morse. But this story tells us about his young life in the police force.
Endeavour was piloted last year, and attracted millions in the ratings - and now four feature length films have been made.
Morse's story has always been told in the city of Oxford - and this is no different. Divya Kohli went to meet the cast and crew.