Bloodtide (audio story)

 was the twenty-second story in Big Finish's monthly range. It was written by Jonathan Morris and featured Colin Baker as the Sixth Doctor and Maggie Stables as Evelyn Smythe.

A pseudo-historical story, it dramatised a portion of the studies made by Charles Darwin on the Galápagos Islands. It also marked the first appearance of the Silurians on audio.

Publisher's summary
The prehistoric Earth is dying. Thunderclouds roll across the skies, cloaking the land in darkness. The seas crash and boil as the rain turns to acid. The remnants of the Silurian race place themselves in suspended animation, deep below the surface.

One day they will awaken and reclaim their world...

The TARDIS has landed on the Galápagos Islands, a desolate outcrop of rocks shrouded in mist and fear.

In the settlement of Baquerizo Moreno, there are rumours that prisoners have been mysteriously disappearing from the gaolhouse. A fisherman has been driven insane by something he saw in the caves. And the Sixth Doctor and Evelyn are not the only new arrivals; there is also a young natural philosopher by the name of Charles Darwin...

Part One
Millions of years ago, a Silurian scientist named Tulok is on trial for experimenting on apes; his sentence is banishment to the planet's surface. On his way there, he encounters a female Silurian named Sh'vak, who offers to sneak him into a stasis pod. He refuses and goes out onto the surface. His creatures will also be banished.

In 1835, The Doctor and Evelyn are unsure of where they are until they encounter a giant tortoise, which tells them that they are on the Galapagos Islands. A little later, they meet up with Charles Darwin, who seems to know The Doctor, though it soons turns out that he thinks The Doctor is Albert Einstein. The Doctor, Evelyn and Charles visit the prison on the island. A man named Emilio is on trial because he claims to have seen devils in a cave by the river; his sister, Greta, pleads with the Judge that Emilio is a good man and is just unwell, but the judge refuses to listen to her and gives Emilio the death sentence.

The Doctor Evelyn and Charles have dinner. Later, The Doctor meets up with Greta and they go to the cell block. They discover that all the cells are empty. They go into one of the cells and the door closes and locks behind them. After a few minutes, a wall opens and Silurians come to take them away.

Part Two
Evelyn talks with Darwin, who has come to the conclusion that evolution is not due to divinity. Meanwhile, the Doctor and Greta are in a Silurian prison under sea level, where they find Emilio. The Doctor puts him into a hypnotic trance to relax, and explains who the Silurians are, which the Silurians overhear. They discuss whether the Doctor is a threat and should be killed, or should be studied. Emilio has become an ape due to his fear of the Silurians, and the Doctor tries to revert this process hypnotically. He succeeds.

A Silurian- Sh'Vak- takes the Doctor away while Evelyn and Darwin explore the islands and look for the Doctor, while Darwin further develops his theories. The Doctor is taken to a laboratory, spotting a modified bacterial culture, and is strapped to a chair. Sh'Vak believes Tulok and herself are the only survivors of the Silurian race, and are trying to get rid of humans because the Silurians were "here first". The Doctor reveals other Silurians exist, and tries to convince Sh'Vak not to start a war. Evelyn and Darwin meet with the governor, who says that the Doctor hasn't been found, and they leave him.

The Doctor realises that the governor of the island, Lawson, is being hypnotically controlled by the Silurians, and they try their hypnotic interrogation on the Doctor, who implores them to make peace with the humans. Meanwhile, Evelyn pieces together that the governor has something to do with the Doctor's disappearance, and the governor tells the Silurians about Evelyn and Darwin posing a threat to their mission because of their connection with the Doctor. Greta and Emilio are attacked.

Evelyn and Darwin reach the prison, and realise it's entirely empty. The governor tries to remotely lock them in like he did to the Doctor, but fails, as the pair get put of the way before the door closes. The Silurians plan an attack on the HMS Beagle, and Evelyn and Darwin are locked into the prison. They find a secret passage and go down the stairs inside. Greta wakes up next to the Doctor, but Emilio has been taken away, and the pair find their cell door open, allowing them to escape. Evelyn and Darwin find the passage leads to what looks like a mausoleum, and see dead Silurians inside the few open coffins. Evelyn and the Doctor find a lift

The Doctor smashes up the governors equipment so that the Silurians can't contact him. The Silurians infect the governor with a flesh eating virus.

Part Three
Greta is told that the Myrka is tracking her because the Silurians implanted a tracking device in her while she was unconscious. Greta chooses to sacrifice herself to save everyone on the ship. The Doctor rescues Evelyn and Charles; Charles goes back to the surface, while The Doctor and Evelyn go to another part of the cave. The Doctor and Evelyn find the Silurians stasis chambers, there is a deceased Silurian in one of them, someone has smashed up the stasis chambers; Sh'vak is listening, and knows that Tulok must've done it.

The Doctor finds a walk-in freezer full of meat, he deduces that the Silurians have been eating the prisoners. Tulok overhears Charles telling Evelyn his theory of evolution. Later Tulok enters the room and tells Evelyn and Charles that human evolution was the result of his genetic engineering, and that he is their god.

Part Four
to be added

Cast

 * The Doctor - Colin Baker
 * Evelyn Smythe - Maggie Stables
 * Charles Darwin - Miles Richardson
 * Captain Fitzroy - George Telfer
 * Tulok - Daniel Hogarth
 * Governor Lawson - Julian Harries
 * Sh'vak - Helen Goldwyn
 * Greta Rodrigues - Jane Goddard
 * Emilio / Lokan - Jez Fielder
 * The Myrka - Rob Shearman & William Johnson

Scientists

 * The Doctor goes by the pseudonym "Albert Einstein".

Authors
The Doctor reads from a book by Herman Melville, declaring Melville to be his favourite author. Evelyn calls Melville pompous and arrogant.

Ships

 * The Doctor and Evelyn meet Darwin while he is on the HMS Beagle.

Theories and concepts

 * Monkton's Theorem states that no intelligent species is likely to leave behind fossils.

Continuity

 * The Silurians appear. (TV: Doctor Who and the Silurians, et al.)
 * The Myrka previously appeared in TV: Warriors of the Deep and PROSE: The Scales of Injustice.
 * The Third Doctor previously claimed to have met Darwin. (PROSE: Island of Death)
 * Many years later, the Seventh Doctor and Evelyn would reminisce about meeting Darwin. (AUDIO: A Death in the Family)
 * The Eighth Doctor later told his companion Charley Pollard that this experience "put [Darwin] off reptiles for life. Well, almost." (AUDIO: The Creed of the Kromon)
 * In a parallel universe in which the Valeyard killed the Sixth Doctor and acquired his seven remaining regenerations, the Valeyard and his companion Ellie Martin visited a Silurian bunker in the Galápagos Islands. This incident was observed by the Time Lord Vansell, Coordinator of the CIA. (AUDIO: He Jests at Scars...)