Endeavour (2012-) is the second spinoff series of Inspector Morse. A prequel set in The Sixties, it relates the early cases of the young Detective Constable Morse, starting with his arrival at Oxford CID.
This show provides examples of:
Actor Allusion: When Abigail Thaw's character first meets Morse she wonders if they've met before. When Morse says no she says 'In another life maybe'.
Call Forward: To Inspector Morse, naturally. The series addresses the origins of elements of Morse's character such as his taste for real ale, his limp and his friendship with Strange. Subverted with the rooftop scenes in "Fugue", which could have provided an origin story for his fear of heights, but it seems that is a story for another time.
Bluffing the Murderer: How Morse wins the day in "Rocket": when he tells the murderer they already have the evidence they need, he replies that he never thought anyone would look there.
Chekhov's Skill: Subverted in "Home". Early on, Morse is established as an excellent shot, and this is brought up a couple more times in the episode. In the end, however, it's Inspector Thursday whose skill with a pistol saves Morse, not the other way around.
Chewing the Scenery: Chief Superintendent Bright in "Rocket", as the pressure of the murder investigation begins to tell on him.
Grammar Nazi: In "Rocket", Morse is sent to keep an eye on a group of anarchist protesters and make sure they don't cause trouble. He can't resist pointing out a spelling mistake on one of their banners.
Have a Gay Old Time: Strange tells Morse his colleagues think he's a "Queer fish, stand offish... rude".
London Gangster: One of them, an old nemesis of Thursday, sets up a nightclub in Oxford during the events of "Home". Said gangster is an associate of the Fletcher Brothers (a Shout Out to the employers of the Villain Protagonist of Get Carter) are implied to be even worse, and he is rumored to have gone to Oxford to escape their wrath.
Mythology Gag: In the pilot, the question of whether Morse's girlfriend at university was called Wendy (as in the books) or Susan (as in the series).
Papa Wolf: Do not go after Thursday's family. You will regret it.
Setting Update: Reaps what the Inspector Morse series sowed in this regard. That series updated novels set from 1970 onwards to the then-present (1987 onwards). Endeavour, which is initially set in 1965, follows the TV chronology, so its setting is 20+ years before the original series, not five.
Shell-Shocked Veteran: Inspector Thursday was clearly traumatized by his experiences in World War II, which left a darkness in him that he does his best to suppress.
Sleazy Politician: Chief Inspector Bright has some definite shades of this, as he's shown on more than one occasion attempting to quash investigations by Morse and Thursday into criminal behavior by people of importance, clearly motivated by a fear that they could hurt his opportunities for advancement if angered (or would help him if he remained on their good side).
Strong Family Resemblance: Combined with Mythology Gag in "Home". Morse's dad doesn't look much like the Endeavour Morse played by Shaun Evans... but he does look remarkably like John Thaw! (This isn't a Casting Gag, though - without the make-up, actor Alan Williams doesn't look like John Thaw at all.)
Tempting Fate: It is, of course, at the very moment that Chief Superintendent Bright is congratulating himself how well the security operation in "Rocket" went, that the news comes in: somehow, he and his men missed a murder being committed under their very noses.
You Look Familiar: The series has so far taken the same attitude toward casting as Lewis, meaning that while guest actors aren't re-used as different characters in this series, actors who've previously appeared in Inspector Morse or Lewis can be brought back in different parts to what they originally played. Notably, "Rocket" has guest appearances by Martin Jarvis (who appeared in Morse) and Jenny Seagrove (who appeared in Lewis).