The Battle of the Tower (audio story)

 was the third story in the audio anthology, Shutdown, produced by Big Finish Productions. It was written by Andrew Smith and featured Jemma Redgrave as Kate Stewart, Ingrid Oliver as Petronella Osgood and James Joyce as Josh Carter.

Publisher's summary
The threat is now clear, and Kate Stewart retreats to UNIT HQ with her most trusted colleagues. She has no choice but to place the Black Archive into lockdown, and the Tower of London is where UNIT will make its stand.

While the capital sleeps, an alien horde is gathering, ready to rise from the shadows to attack Earth's greatest defence force inside its own stronghold.

The Tower is infiltrated, and UNIT must hold the line. At any cost. Lock and load...

Plot
One of the Tengobushi attacks the UNIT aeroplane and, whilst Josh struggles with him, Kate and Osgood try to pilot it. Josh manages to get the Tengobushi off of the plane and lands safely on the ocean, after which they manage to return to the Tower of London and go to high-alert with the intention of going into lockdown once the tourists have left. Osgood finds the Kamishi energy cell in the Black Archive and Kate has Josh kidnap Lyme and bring her to the Tower. Lyme admits that Professor Harrison told Dr Eastwood about the energy cell and that he ended the experiments shortly before his death.

Sir Peter arrives at the Tower and has Lyme released. Kate orders Sam to be sent to Santiago ahead of Lyme and explains to Sir Peter about the imminent Tengobushi attack. She meets with Dokan and Chiso near the White Tower and goes to check on Osgood when her work on the energy cell causes a tremor. Josh follows the Kamishi to the London Underground and into the tunnel to their secret base, but he is soon forced to flee and returns to the Tower before lockdown. Sir Peter attempts to leave before the battle begins, but the Kamishi raise an energy field through which humans cannot pass; to get around this, Osgood sends out the ravens of death.

The Tengobushi test UNIT's defences and Kate has Josh bring Osgood and the energy cell from the Black Archive to her. Osgood contaminates the air in the archive with necrotising radiation before they leave and, on Kate's orders, they shut themselves inside the Jewel House for protection from the Tengobushi, who have caused damage to the underground tunnels using energy missiles. Osgood and Josh remembers the Saturnine Star from their induction and insert it into a UNIT insignia, revealing a hidden passageway which leads them to the White Tower. UNIT soon realise that the attack is a diversion and that the Tengobushi are using unused tube lines to sneak in.

Dokan enters the base with more Tengobushi and Kate invokes Operation Swordfish, having Josh take Sir Peter to the assembly point beneath St Thomas's Tower to escape by submarine through Traitor's Gate with the other evacuees whilst Osgood prepares to use the energy cell and an Antarian pulse grenade against the invaders. Kate invites Dokan to the Bloody Tower and uses an anti-gravity device to escape, leaving him to be wounded by the energy cell. She joins Osgood and Josh in the submarine, hoping that Dokan will have realised how big a threat humanity is and leave Earth. Dokan's masters have sensed Kamishi energy signatures at the South Pole and order him to be ready for their arrival.

Cast

 * Kate Stewart - Jemma Redgrave
 * Osgood - Ingrid Oliver
 * Captain Josh Carter - James Joyce
 * Felicity Lyme - Alice Krige
 * Sir Peter Latcham - Nigel Carrington
 * Dokan - Dan Li
 * Chiso / Tengobushi Assassins - Akira Koieyama

Worldbuilding

 * Richard is Lyme's driver.
 * Lyme has a flight to Santiago.
 * Three queens of England, two saints and four bishops were imprisoned in the Tower of London. Of the bishops, three, Hugh Latimer, Nicholas Ridley and the Archbishop of Canterbury Thomas Cranmer were later tried and burned as heretics.
 * Sir Peter has the authority of the Defence Secretary.
 * Josh mentions Diagon Alley, a fictional location in the Harry Potter series.
 * Kate has new batteries put in the ravens of death.
 * The Saturnine Star was given to Alistair Gordon Lethbridge-Stewart by an ambassador from Andromeda.
 * Osgood uses an Antarian pulse grenade.

Continuity

 * General Avery has gone missing. (AUDIO: Death in Geneva)
 * Sam is in Johannesburg. (AUDIO: Death in Geneva)
 * Atkins who worked in the Black Archive was expected to be disappointed that the Tower of London had been destroyed on "his first day of work". When Clara Oswald met him, "Kate Stewart" explained to her that his memory was wiped every day. (TV: The Day of the Doctor)