Changes from the Book
The Great Dane, Brutus, and Red Rackham's first mate, Diego the Dreadful, are notably absent. Also, when Captain Haddock takes Tintin out of the latter's apartment to show him the painting of the The Unicorn, someone is shown watching them and then breaking into Tintin's apartment, whereas in the book it is only revealed that there was a robbery when Tintin arrives home and finds his model Unicorn missing. This episode depicts this break-in. When Nestor knocks Tintin on the head, Tintin faints, whereas in the book he is simply shown rubbing the spot. Also, near the end, both of the Bird Brothers tell what happened at Marlinspike Hall, wheras in the Book, Max escapes in his Car and only Gustav told the story. Furthermore after being defeated, the Bird brothers are arrested on the grounds rather have Max escaping and having to be arrested at the national border.
Gustav Bird's role is downplayed and he doesn't seem to talk as much as he does in the book. Finally, a change was made to the scene in which Tintin is kidnapped and taken to Marlinspike Hall: rather than two unknown "delivery men", as depicted in the book, it is the Bird brothers (Max and Gustav) themselves who kidnap him. Also, the "speaking tube" in Marlinspike Hall where Tintin talks through it to the Bird brothers is replaced with an intercom. Also in the scene where Thomson and Thompson meet the pickpocket Artistides Silk, Silk doesn't mention that he's a kleptomaniac in the TV episode unlike the book.
- Colin O'Meara - Tintin
- Susan Roman - Snowy
- David Fox - Captain Haddock, Sir Francis Haddock
- John Stocker - Detective Thompson
- Dan Hennessey - Detective Thomson
- Elizabeth Dufresne - Mrs. Finch
- Keith Knight - Gustav Bird, Crabtree
- Vernon Chapman - Nestor
- Peter Meech - Radio Announcer
- Captain Haddock incorrectly states that The Unicorn was part of Charles I's fleet, when it was actually Charles II who ruled Great Britain in 1676.
- In part 2, when the detectives explain what would have happened if the Captain had been the culprit for attacking Mr. Sakharine, Tintin's shirt collar is blue.
- When we first see Mr. Silk in his apartment, he has no side hair.