Casualties of Time (audio story)

 was the eighth and final story in the fifth series of The Fourth Doctor Adventures, produced by Big Finish Productions. It was written by Nicholas Briggs and featured Tom Baker as the Fourth Doctor, Lalla Ward as Romana II, John Leeson as K9 Mark II, David Warner as Cuthbert, Toby Hadoke as Mr Dorrick, David Troughton as The Black Guardian and Jez Fielder as The White Guardian.

It was the second part of the series finale, following on from The Pursuit of History.

Publisher's summary
The TARDIS crew have unknowingly become embroiled in a web of deceit. A trap has been laid across time and they have no possible means of escape. Destiny has ensnared them.

The Doctor is finally getting the chance to see the Conglomerate's work at first hand. Romana is working to save the alien Laan once and for all. K9 is returning to Ancient Britain in search of an unusual power source.

The Doctor, Romana and K9.

Today one of them will die.

Plot
to be added

Cast

 * The Doctor - Tom Baker
 * Romana - Lalla Ward
 * K9 / The Oortag - John Leeson
 * Cuthbert - David Warner
 * Mr Dorrick - Toby Hadoke
 * The Black Guardian / Edge - David Troughton
 * Drudger / Ecidien Cerebus Bird / The White Guardian / Salonu Prime - Jez Fielder
 * The Laan / Salonu - Jane Slavin
 * Conglom-net Computer - Lisa Bowerman

Crew

 * Cover Art - Anthony Lamb
 * Writer & Director - Nicholas Briggs
 * Executive Producers - Jason Haigh-Ellery and Nicholas Briggs
 * Music and Sound Design - Jamie Robertson
 * Producer - David Richardson
 * Script Editor - John Dorney

Worldbuilding

 * The Oceanic States and the Asiatic States are the two major power blocs on Earth. By 2071, their war is at a stalemate, and is on the front of the emerging United Earth government, which will have an Earth presidency.
 * The new Conglom-AIs can process information a thousand times faster than the speed of thought, and are made from the super-conductive alloy tritonium, which came from the Salonu ship.
 * The Oortag Leader explains that all Oortag are named "Oortag."
 * The Conglom-AI creates an avatar of Romana within the time engine to keep her safe while she's in the Time Analysis Chamber, or T.A.C.
 * The avatars created are of a being as it is now: if it copies the Laan in their weakened-state, the avatars will be weak as well.
 * The Iron Age was characterised by the large adoption of iron and steel.
 * Cuthbert uses a bazooka to fire at the Salonu ship.
 * He says that history always has its casualties.
 * Nitrogen conversion sucks up all the nitrogen in the immediate area into a spaceship's reactor, leaving the atmosphere oxygen-rich, making it highly flammable.
 * K9 tries to explain to the Salonu that their conversion will damage the timelines.
 * The Black Guardian is, as the Doctor puts it, well-informed but unwilling to act, and wants to unleash chaos in the timelines.
 * Paradoxes can be caused by freak time eddies and meddling time travellers.
 * The Black Guardian travelled back along the Doctor's timeline to exact his revenge.
 * Cuthbert is a construct inserted into spacetime and merely exists in a causal loop, creating his own history. As such, he has no childhood, and cannot remember his father, mother, or where he grew up. He is a paradox, with no beginning and no end. The Black Guardian designed him as a trap for the Doctor.
 * Although Cuthbert is unable to bring the Salonu ship down, it loses power and crashes anyway, preserving history. The Doctor describes it as "Time itself" healing the wound, but later wonders if it wasn't the White Guardian doing his own interfering, as the ship crashing is an established part of history and forms the centre of a temporal anomaly.
 * The avatar of the Fourth Doctor releases the Laan from the time engine, their own time energy restoring them.
 * The Doctor is aware of the Ecidien Cerebus Bird, but his mind wants to forget it. The Bird keeps a back up of his mind.

Continuity

 * There are two major power blocs on Earth in the late 21st century. (TV: Warriors of the Deep)
 * Romana explains that because he's been travelling in time longer than her, the Doctor's artron energy would be much stronger. (TV: The Deadly Assassin)
 * The Black Guardian again shows carelessness for a few lives compared to the majority. (TV: The Armageddon Factor)
 * The Black Guardian cannot be seen to act in person. (TV: Mawdryn Undead)
 * The Black Guardian claims that the time travellers' attempts to elude him had no effect, (AUDIO: The Auntie Matter, Wave of Destruction) and that he's been watching them. (PROSE: The Well-Mannered War)
 * The Ecidien Cerebus Bird says "the time is approaching" and drags the Doctor into the TARDIS. (AUDIO: The Pursuit of History)
 * The Doctor explains the Bird is connected to the telepathic circuits, (TV: The Time Monster et al) and has access to his symbiotic nuclei. (TV: The Two Doctors)