History Trivia / SherlockS04E01TheSixThatchers

* ActorAllusion: the 'Amo' codeword, and specifically Sherlock's conjugating the verb to Mycroft ("Amo - Amas - Amat") is likely a ShoutOut to Benedict Cumberbatch's role in ''Film/{{Atonement}}'', in which the character of Lola says the same thing to his character.

* WhatCouldHaveBeen:
** The scene with Toby was meant to be much more frantic, but neither of the dogs they got to play Toby really wanted to be active.
** Gatiss and Moffat always knew Mary was going to die, but they briefly considered having her die in the finale. But they felt that would lessen the emotional impact so they had her die in the premiere.

* RealitySubtext: Shortly before this episode premiered, Creator/MartinFreeman and Amanda Abbington announced that they had broken up, and were AmicableExes. Whether that makes Mary's death better or worse is up to you.

* ActorAllusion: the 'Amo' codeword, and specifically Sherlock's conjugating the verb to Mycroft ("Amo - Amas - Amat") is likely a ShoutOut to Benedict Cumberbatch's role in ''Film/Atonement'', in which the character of Lola says the same thing to his character.

* ThrowItIn: While filming the scene where Sherlock uses a bloodhound to track blood found on a bust, the dog refused to move. So Creator/MarkGatiss and Creator/StevenMoffat wrote a scene about it on the street. There was also a backup dog that '''''also refused to move'''''.

* ThrowItIn: While filming the scene where Sherlock uses a bloodhound to track blood found on a bust, the dog refused to move. So Gatiss and Moffat wrote a scene about it on the street. There was also a backup dog that '''''also refused to move'''''.

* Shortly before this episode premiered, Freeman and Abbington announced that they had broken up, and were AmicableExes. Whether that makes Mary's death better or worse is up to you.

* CastingGag: The grieving father is played by Charles Edward, who played Conan Doyle himself in ''Series/MurderRooms''.

* Shortly before this episode premiered, Freeman and Abbington announced that they had broken up, and were AmicableExes. Whether that makes Mary's death better or worse is up to you.

* WhatCouldHaveBeen: Gatiss and Moffat always knew Mary was going to die, but they briefly considered having her die in the finale. But they felt that would lessen the emotional impact so they had her die in the premiere.

----

* WhatCouldHaveBeen: Gatiss and Moffat always knew Mary was going to die, but they briefly considered having her die in the finale. But they felt that would lessen the emotional impact so they had her die in the premiere.

* ShoutOut: The A.G.R.A team rescuing the hostages in a flashback was punctuated by one of them saying: [[VideoGame/MetalGear "What took you so long"?]] Furthermore, [[spoiler: their eventual failure, the breakup of the unit and the torturing of their allies is pretty much the plot of ''VideoGame/MetalGearSolidVGroundZeroes'']].

* CastingGag: The grieving father is played by Charles Edward who played Conan Doyle himself in ''Series/MurderRooms''.

* ThrowItIn: While filming the scene where Sherlock uses a bloodhound to track blood found on a bust, the dog refused to move. So Gatiss and Moffat wrote a scene about it on the street. There was also a backup dog that '''''also refused to move'''''.

* CastingGag: The grieving father is played by Charles Edward who played Conan Doyle himself in ''Series/MurderRooms''.

* CastingGag: The grieving father is played by Charles Edward who played Conan Doyle himself in ''Series/MurderRoomsTheDarkBeginningsOfSherlockHolmes.''