The Music Lesson

In 1925, during a piano lesson, Henry Arbinger asks his music teacher, Timothy Drake, to play something exciting, and is introduced to a melody called ‘The Devil’s Chord’. But as Timothy Drake plays the piano’s lid suddenly drops and then knocking is heard from inside the piano. Maestro then emerges from the piano and reveals that Henry’s name is short for Harbinger before disposing of the young lad. Maestro then announces that Timothy Drake is a genius for unlocking ‘the lost chord’. Maestro then consumes the music from his soul.

In the TARDIS, Ruby asks The Doctor to take her to see the Beatles record their very first album. When the TARDIS materialises on Abbey Road in London, on the 11th February 1963, they venture out and start exploring and enter the EMI Recording Studios that will become the famous Abby Road Studios. Inside they take over a tea cart allowing them to enter one of the recording studios where they come across The Beatles in the midst of a recording session. But as the Beatles start to play The Doctor and Ruby are disappointed and confused by a poorly composed song about Paul McCartney's dog. They also peek into separate sessions with Cilla Black, and an entire orchestra, who are also performing very poorly composed music.

Sometime later in the studio’s cafeteria The Doctor theorises to Ruby that music’s sudden disappearance is leading humanity to a dark future. They discover from John Lennon and Paul McCartney that the band, as well as the rest of the world, has stopped caring about music since the early 20th century and they plan on finishing the album before retiring to normal everyday lives. The Doctor fears this loss of interest in music will alter humanity's future. But John and Paul react angrily when The Doctor and Ruby try to reassure them of the importance of music.

Maestro

The Doctor has a piano taken up to the studio’s roof and he implores Ruby to play a tune, and so she plays a sad song she wrote for a friend. The music attracts the attention of Londoners, who emotionally react. However, as Ruby continues to play it also gains the attention of Maestro. As the piano violently shifts, interrupting Ruby’s playing Maestro emerges from the piano while laughing. The Doctor recognises this laugh as the same as The Toymaker's giggle. Petrified, The Doctor flees into a cellar, and uses his screwdriver to silence the environment around them as Maestro searches for them.

Then in the distance an elderly lady begins playing Claire de Lune, distracting Maestro who kills the elderly lady. The Doctor suspects Maestro to be part of The Toymaker’s legions: The Pantheon. Ruby tries reassuring him, but The Doctor fears Maestro’s powers. To convince Ruby of the effect Maestro will have on humanity, The Doctor takes Ruby back to 2024, where they find London has been devastated by a nuclear war.

The Zebra Crossing

Before they can return to 1963 London they are interrupted by Maestro, who it is revealed is a child of The Toymaker with similar powers and who is growing stronger by consuming all music. Maestro’s ultimate aim is to steal The Music of the Spheres.

During this confrontation it is revealed that the only way to defeat Maestro, is for The Doctor to find the correct chord. Maestro reveals this information believing The Doctor is incapable of doing so. Maestro then plays tunes that affect the TARDIS. The Doctor though is able regain control allowing them to return to 1963.

Back in Abbey Road Studios, The Doctor plugs his sonic screwdriver into a control booth and uses John Lennon’s guitar to try and find The Notes of Banishment. But then Maestro uses physical music notes to kidnap Ruby, disabling the sonic screwdriver, and threatens to consume her music. Ruby begins singing Carol of the Bells and it starts to snow inside the studio. This confuses Maestro due to the power from deep within her soul. The Doctor realises that this is because this is the Christmas song that was being played when Ruby was left outside the church. To stop the music Maestro frees Ruby, who falls to the ground but is caught by The Doctor. The Doctor then uncovers a piano (known as the Mrs Mills Piano) which he uses to fight Maestro. They engage in a music battle, The Doctor on piano, Maestro on violin.

The Beatles

Ruby joins The Doctor on the piano and between then they force Maestro to break the violin. The Doctor then discovers The Notes of Banishment, but plays a bum note, allowing Maestro to regain full power. Maestro flings the piano down a corridor, and traps The Doctor and Ruby in instruments. In the corridor John Lennon and Paul McCartney come across the piano, with The Doctor’s partially played rendition of The Notes of Banishment floating above it. They are able to complete the chord, causing the piano to drag Maestro inside so freeing The Doctor and Ruby. But Maestro, before the piano lid closes, announces to The Doctor that ‘The One Who Waits is almost here’.

With music returned to the world, everyone starts to sing and dance - including The Doctor and Ruby who engage in a musical number before leaving in the TARDIS. But they are unaware that they are being watched by the young Henry Arbinger.