When Morse refers to "Hardy" in reference to his recent stay in the West Country, he means, of course, the novelist and poet Thomas Hardy, a native of the area. Not understanding this, Strange laughingly refers to "another fine mess" - the catchphrase of the American comedian Oliver Hardy, of Laurel and Hardy fame.
In addition to the name Lermontov suggesting the controlling character in The Red Shoes (1948), the character names "Belasco" and "Fischer" refer to a very different British film, the horror movie The Legend of Hell House (1973).
On the basis of this first episode, it looks as if the final season of "Endeavour" may round up a number of loose ends from story-lines of previous seasons. Quite apart from a brief, passing reference to "Mimi", the pop singer featured in "Canticle", there are references to "Landesman Construction", the crooked building firm featured in "Neverland" and to "Blenheim Vale", the children's home featured in that story (with a brief flashback to Peter Jakes's anguished confession), as well as return appearances from Jack Bannon as Sam Thursday (whose disappearance from the army is not yet fully explained) and Simon Harrison as the corrupt ex-DCI from Season Six, Ronnie Box, now working as a private detective (having been released from prison rather earlier than one might have expected). The promotion suggested for Thursday is in "Carshall New Town", the (fictitious) town where Morse began his police career, as mentioned in the pilot episode. There are also references to "young Mr. Burridge" at the Oxford department store featured in "Sway" and to Fred Thursday's ne'er-do-well younger brother Charlie, featured in two stories ("Cartouche" and "Icarus") in Season Five.
Although the story begins with Morse optimistic about his treatment for alcoholism and telling Thursday "I'm cured, all right", nonetheless, he has begun drinking alcohol again by the end, if not to excess. Thus, his line, "I'm cured, all right" is quite possibly a deliberate reference to the last line of Kubrick's "A Clockwork Orange" ("I was cured, all right"), when the brainwashed Alex is starting to have violent and depraved desires once again.
The tradition of Colin Dexter cameos continues. A poster advertising "Dexter's Satchels" appears on the wall in Burridges men's footwear department. It features a photograph of the original Inspector Morse author, now deceased.