Animal Instinct (audio story)

Animal Instinct was the second story of the audio anthology, The Diary of River Song: Series Five. It was written by Roy Gill and featured Alex Kingston as River Song and Geoffrey Beevers as the Decayed Master.

Publisher's summary
On a world where vicious beasts stalk ancient ruins, Professor Song teaches a student the finer points of archaeology.

But then she meets an incarnation of the Master who is desperate to survive.

And if they are going to escape this place alive, they all must work together.

Plot
River and Luke, a student who joined her as part of his practical exam, break into the tomb of a supposed Chasca Minorian sun god and attempt to take an Obsidian Mirror from the hands of the Master. The Master awakens, initially assuming that Luke is the Doctor because of his dress sense, and realises that his trap for the Doctor has failed thanks to the tomb being moved from Chasca Minor to Chasca Major some centuries ago. Believing herself responsible for any chaos that the Master might unleash, River makes Luke give the Master his clothes and knocks him out to provide security with a distraction whilst she and the Master escape.

Walking through the Feast Dance carnival, River agrees to take the Master to Chasca Minor in the Condor to recover his TARDIS. Captain Dav Christos does not believe that the Condor can make the journey, but the Master manipulates him and Adella Franz with promises of riches. They take off after Luke joins them and River confides in Luke that she has slipped a biotracker tag onto the Master so that she can track him with her vortex manipulator. A flare of gamma radiation causes them to crash and they find that the Master's relay system, which caused the flare, is keeping the moon in eternal daytime.

The group head to the Great Ziggurat of Chasca Minor and hide up a tree from a humanoid cat wearing glasses, but the Master knocks the injured Captain Christos down to be eaten, giving the others the opportunity to escape. The Master reveals that the humanoid cats, called Therians, are a mutated strain of the Chasca Majorians who were dumped on the moon and he created the relay to keep them from being feral as they are in the night. However, their glasses counteract this. River, the Master and Adella enter the Sun Chamber whilst Luke, who has his arm stuck in a trap, is locked outside when the doors close. The Therian Leader arrives and kills Adella.

Upon disabling the relay, River and the Master run. He attempts to hypnotise her into helping restore his TARDIS rather than leaving in the Condor, believing that he has been subtly influencing her through the reversed biotracker, but this is not the case and River is naturally pragmatic without his influence. They flee from a Therian to the Condor and the Master tortures it; River recognises it as Luke, transformed as a blessing by the ziggurat, and restores him with a high-energy, super-lumiscent blast to rewrite his DNA. She plans to do the same for the other Therians, but they show no interest and Luke tells her that it is not her choice. She gives the Master's TARDIS's capacitor to them to make their choice, leaving the Master to their mercy.

On the way back to Chasca Major, River tells Luke that he has passed his final exam and they detect a flash from Chasca Minor indicating that the Therians have either used or destroyed the capacitor. River asks Luke if he does indeed want to return home rather than go back to the Therians, which he says is the case.

Cast

 * River Song - Alex Kingston
 * The Master - Geoffrey Beevers
 * Luke Sullieman - Timothy Blore
 * Dav Christos / Therian Leader - Delroy Atkinson
 * Adella Franz / Therian - Emily Woodward

Worldbuilding

 * Luke wears tweed and a deerstalker. River makes him lend his outfit to the Master.
 * River uses a sonic pen torch and tells Luke that "he baggsied the best name". It doubles as a torch and does not work on stone.
 * River describes Luke's university as a backwater.
 * Luke brings a thermos of tea.
 * The Master's tomb was moved from Chasca Minor to Chasca Major by a relic hunter from Daedalus VI.
 * River has been intrigued by the Great Ziggurat of Chasca Minor for some time.
 * The Master possesses an Obsidian Mirror.
 * River compares the Master's style to Moriarty.
 * River slips a biotracker tag onto the Master.
 * River has field glasses.
 * Luke has to write a dissertation.
 * The Master asks, "Who was it said 'Humans should never invite their ancestors round for dinner?'" This both a reference to The Hitchhiker's Guide to the Galaxy and its author, the late Douglas Adams who both wrote and script-edited episodes of the classic series. This is also asked by the Seventh Doctor in the Season 26 story Ghost Light.
 * Luke is reminded of the Toltecs.
 * River mentions The Crystal Maze.
 * Chasca Major orbits Chasca Orionsis.
 * River says that she was practically worshipped in 1970s Vegas.

Continuity

 * River calls herself a psychopath. (TV: The Angels Take Manhattan)
 * River is a fan of handcuffs. (TV: Forest of the Dead, Flesh and Stone)
 * The Master agrees that disguises are fun. (TV: Terror of the Autons, etc.)
 * River says that legends often end up being the Doctor. (TV: The Pandorica Opens)
 * River reveals to the Master that she married the Doctor. (TV: The Wedding of River Song)
 * The Master suggests that he should look into River's background. He will eventually do so by the time of his War incarnation. (AUDIO: Concealed Weapon)
 * The Master will later be stranded on another planet inhabited by human-feline hybrids, the Cheetah World. (TV: Survival)