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, and use it to escape into the cave Emilio originally saw the Silurians in, while Tulok allows them to escape, ordering them not to be captured. Evelyn and Darwin have been spotted by the Silurians, and are captured. The captain of the Beagle, Fitzroy, helps the Doctor and Greta into the ship, and something big is seen in the water.

Part Three
The Doctor shepherds everyone below decks, and tells them that the creature is electrically charged, so touching it would mean death. The Doctor uses oil to set fire to the ocean, but this fails to drive the creature- the Myrka- away. 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.

Tulok explains that he let the humans (well, human and Doctor) go so they could be destroyed on their home turf of the Beagle, and believe the ship to have been destroyed as they see the Myrka moving away from the ship. They have prepared a bacterial culture that is carried by an airborne microbe. It will wipe out all humans except the newborn, with the infected dying in minutes. Fitzroy and the Doctor set out to rescue Evelyn and Darwin. Evelyn looks at the seaweed they've been given to eat while Darwin has a crisis of faith, and the Doctor talks to the governor. Governor Lawson is hypnotised by the Doctor to tell him where Evelyn and Charles Darwin are.

Lawson has been imprisoning innocent people and provide the Silurians with specimens (humans) for their 'collection', and the Doctor smashes up the governors equipment so that the Silurians can't contact him. The Silurians take the hypnosis as a betrayal, and infect Lawson with the disease. The Doctor arrives at the Silurian hibernation chamber, finding that the Silurians never woke up because someone sabotaged the controls, so they all died instead. The Doctor finds a walk-in freezer full of meat, he deduces that the Silurians have been eating the prisoners, and Sh'Vak captures him and Fitzroy.

The Silurians infect Lawson with the bacteria, and he dies. The Doctor and the humans are reunited in the same cell, and Tulok overhears Charles telling them his theory of evolution. Tulok reminisces that his generically modified creatures became what are now humans, and how Tulok was joined by Sh'Vak, and he declared revenge on his former people. In the present, the settlement has been destroyed, except for the infants, who they plan to make into their slaves. The Doctor declares life's persistence to be the real miracle while Darwin declared that a god who did not create humans, or the earth, just be no god at all. At this, Tulok enters the room and tells them that human evolution was the result of his genetic engineering, and that he is their god.

Part Four
Tulok hypnotizes Darwin and Fitzroy to follow him; The Doctor explains that the Silurians plan to destroy humanity to take their world back. Tulok is making the hypnotised humans load vials of the bacteria into submersibles, ready to be released on each continent of Earth. Sh'Vak overhears the Doctor explain to Evelyn that someone has purposefully killed the sleeping Silurians, and knows that Tulok must have done it. The Doctor whispers to Evelyn that he told her this to make sure Sh'Vak overheard. She returned to their cell after confirming their story by checking the hibernation chamber and seeing the sabotage, and explains that she had saved Tulok, long ago, and that she is turning against Tulok and wants to allow humanity to develop.

Sh'Vak tells the Doctor about Tulok's plan. All the canisters of bacteria have been loaded onto the submersible, but Tulok realises something is wrong, even as Sh'Vak declares she will kill him. Fitzroy and Charles are returned to the cell, and the Doctor snaps them out of the hypnosis. Sh'Vak confronts Tulok, who admits his crime. He uses his psychic powers to kill her. Darwin and the Doctor figure out that humanity may be able to resist the Silurian hypnosis under the right circumstances. Tulok overhears this through the bug planted in the cell, and orders the humans killed. Sh'Vak managed to survive, and returns to rescue the Doctor's party, explaining that she killed the soldier sent to kill them.

The Doctor contacts Tulok over a radio from the Silurian control bunker cheerily, not telling him that Sh'Vak survived. He overloads their hydrogen fusion reactors (giving them 15 minutes until they burst) and commands Tulok to meet up with him. Evelyn goes down to the submersible with a device, given to her by the Doctor, to hide on the ship. Sh'Vak hides, and Tulok arrives. Charles and Fitzroy resist Tulok attempting to mind control them by focusing on something they believe in- Fitzroy has religion, but Charles has lost his, so he focuses on his theory of evolution instead.

Evelyn hides the device on the submersible, but is discovered by a Silurian. Evelyn pretends to be under mind control, escaping successfully, while the Doctor tells Tulok that he has failed, because humanity is free and powerful in itself. Tulok leaves, declaring that he will have his revenge. The Doctor tells them that Sh'Vak helped them to resist the telepathy, as mankind hasn't changed all that much, but she is now weak from this effort. The psychic strain was too much for her, and she tells the Doctor to tell her story to other Silurians in other areas.

Tulok and another Silurian escape in the submersible, but the Doctor and team- now reunited with Evelyn- use the homing device that Evelyn hid in the submersible to call the Myrka to the submersible. The Doctor and humans escape from the bunker, now blown up from the overloaded hydrogen fusion reactors, in the lift, whilst the Myrka destroys the submersible. With the bunker, the jailhouse was also destroyed, and the Doctor hints that the Silurians may return, but not for another century. The settlement will be left in peace, now that everyone there is dead and the disease has burnt itself out. The Doctor asks the captain and Charles not to mention them or the Silurians, and tells Charles to keep an eye out for Alfred Wallace. Evelyn and the Doctor depart for the TARDIS.

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".
 * The Doctor and Evelyn meet a young Charles Darwin, who the pair prompt into developing his theory of evolution.
 * The Doctor tells Darwin to keep an eye out for "a chap called Alfred Wallace", suggesting that he could go and give Wallace some moral support, a notion of which Evelyn dissuades him.

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...)