History Recap / DoctorWhoS40E2TheDevilsChord

** When the Maestro draws the music out of Ruby, before "Carol of the Bells" we get a diegetic appearance by "Flavia's Theme", Murray Gold's famous signal that something timey-wimey is happening.

* TheCameo: For the first time in 19 years, Music/MurrayGold appears onscreen AsHimself, playing the piano during "There's Always A Twist At The End".

* AvengingTheVillain: The Toymaker warned the Doctor in "[[Recap/DoctorWho60thASTheGiggle The Giggle]]" that his legions would arrive in the universe, [[SubvertedTrope but the Maestro thanks the Doctor for banishing their father]].

* StevenUlyssesPerhero: In the cold open, the Maestro asks Timothy Drake for the name of the boy who he tried to teach the piano to, and then [[EvilLaugh cackles]] when his name, Henry Arbinger, spells out "Harbinger".

* AlternateHistory: Due to the Maestro's interference in the 1920s, music as a concept has become looked down upon by the 1960s, with Paul [=McCartney=] and by extension the rest of the Beatles only forming for monetary gain. The Doctor also finds a newspaper detailing a threat the USSR has made towards Finland, showing that the politics of this world are being affected by the lack of music as well. This eventually culminates in the Doctor and Ruby [[spoiler: returning to 2024 to discover London (and presumably the rest of the world) has become a desolate wasteland, due to a nuclear war breaking out, as without music no one could express themselves except through violence.]]

* AmbiguousSituation: Susan's fate has been left unresolved since the revived series began, and up until now it had been presumed by most fans she was deceased. However in this episode, the Doctor admits for the first time that he himself doesn't know what happened to her. So she could've died in the Time War, or in the Master's genocidal rampage against Gallifrey... or she could still be out there somewhere.

* ItOnlyWorksOnce: Invoked by the Doctor. It ''is'' possible to trick and even defeat a god, but any solution you come up with will only work once. This is vividly demonstrated during the climax, where the Maestro completely shrugs off and seemingly ''breaks'' (or at least damages) the Sonic Screwdriver after it was previously used to mute all sound in their vicinity.

** According to the credits, series composer Murray Gold makes an appearance AsHimself.

* ThemeTuneCameo: The theme tune is played on the TARDIS jukebox at the beginning of the episode, the Maestro also plays part of it a few times.

* AlternateHistory: Due to the Maestro's interference in the 1920s, music as a concept has become looked down upon by the 1960s, with Paul [=McCartney=] and by extension the rest of the Beatles only forming for monetary gain. The Doctor also finds a newspaper detailing a threat the USSR has made towards Finland, showing that the politics of this world are being affected by the lack of music as well. This eventually culminates in the Doctor and Ruby [[spoiler: returning to 2024 to discover London (and presumably the rest of the world) has become a desolate wasteland, due to a nuclear war breaking out, as without music no one could express themselves except through violence.]]
* AbstractEater: The Maestro can eat music, but unique from other examples they can also eat music that goes unplayed, meaning that engineering the death of anyone that can play music still feeds into their power.

* ContrastingSequelAntagonist: Compared to the Toymaker, who wanted everyone to play his games, the Maestro wants to be the sole person that plays music. Whereas rules of the game define the Toymaker, the Maestro has no qualms about cheating. While the Toymaker kept his first victim alive to torment, the Maestro kills theirs.

** When the Maestro draws the music out of Ruby, before "Carol of the Bells" we get a diagetic appearance by "Flavia's Theme", Murray Gold's famous signal that something timey-wimey is happening.

* CreatorCameo: The old lady who is [[DeathByCameo killed by Maestro]] while playing the piano is played by June Hudson, a 1970s BBC costume designer who worked on both ''Doctor Who'' and ''Series/BlakesSeven''.

* ItOnlyWorksOnce: Invoked by the Doctor. When dealing with gods a solution will only work once.

* SurprisinglyHappyEnding: The Doctor warns Ruby that being around him means "[[PlotTwist there's always a twist at the end]]"-- then winks at the camera, and the episode then ends on a musical number titled "There's Always a Twist at the End".

* AlternateHistory: Due to the Maestro's interference in the 1920s, music as a concept has become looked down upon by the 1960s, with Paul Mccartney and by extension the rest of the Beatles only forming for monetary gain. The Doctor also finds a newspaper detailing a threat the USSR has made towards Finland, showing that the politics of this world are being affected by the lack of music as well. This eventually culminates in the Doctor and Ruby [[spoiler: returning to 2024 to discover London (and presumably the rest of the world) has become a blasted wasteland, due to a nuclear war breaking out, as without music no one could express themselves except through violence.]]

* ArtisticLicenceHistory: The episode is set in February 1963 and features Cilla Black-- but she hadn't been signed yet at the time (she was signed in September that year) and so shouldn't have been at the EMI Recording Studios. Also, John Lennon is wearing the round spectacles that would become his iconic accessory later in the Sixties (probably to identify him to the audience). That said, all this may be justified by AlternateHistory being explicitly in play, with the Doctor finding a news article about the USSR issuing a threat towards Finland, something that never happened in "correct" history.

* AlternateHistory: Due to the Maestro's interference in the 1920s, music as a concept has become looked down upon by the 1960s, with Paul Mccartney and by extension the rest of the Beatles only forming for monetary gain. The Doctor also finds a newspaper detailing a threat the USSR has made towards Finland, showing that the politics of this world are being affected by the lack of music as well. This eventually culminates in the Doctor and Ruby [[spoiler: returning to 2024 to discover London (and presumably the rest of the world) a blasted wasteland, due to a nuclear war breaking out, as without music no one could express themselves except through violence.]]

* LeaningOnTheFourthWall: After eating Timothy Drake's inner music, the Maestro glares right at the viewer, before [[DiegeticSwitch tapping out the beginning of the show's theme]].

* ArtisticLicenceHistory: The episode is set in February 1963 and features Cilla Black-- but she hadn't been signed yet at the time (she was signed in September that year) and so shouldn't have been at the EMI Recording Studios. That said, this may be justified by AlternateHistory being explicitly in play, with the Doctor finding a news article about the USSR issuing a threat towards Finland, something that never happened in "correct" history.