DOCTOR WHO IN DETAIL

China, 1807: As a storm starts people rush to get inside their houses. Outside a woman, Madam Ching, heads towards a statue. A man, Ying Wai, goes to confront her, and finds her chipping away at the statue with her knife. The statue begins to crack. Ching picks up a fragment and the statue shatters. When Wai looks the last thing he sees is the occupant of the statue - a Sea-Devil.

The TARDIS materialises close by on a beach. On the beach the Doctor feels an odd pain through her ear jewellery and, testing a theory, tries skimming a stone into the sea. When it bounces off something in the sea the Doctor's sonic screwdriver detects a kinetic hyper curve, which could be responsible for pulling the TARDIS four centuries off course.

Hearing screams the Doctor, Yaz, and Dan, rush to the nearby village where people are running from demons. When they get there they find most of the villagers have been killed. The Doctor confronts the demon - a Sea Devil. The Sea Devil reveals it is looking for something, and moments later the Sea Devil's ship appears - floating over the land. The Sea Devil takes a giant leap and lands on the deck of the ship which is crewed by more Sea Devils.

When the Sea Devils' ship disappears Ching recovers, and the Doctor stops her being killed by Ying Ki in revenge for the death of his father. Ching tells the Doctor that the statue contained information about treasure that she was seeking - the lost treasure of the Flor de la Mar. Dan recognises it as a ship that went down of the coast of Sumatra. Ching adds that legend said it had been found by the great captain Sin Ji-Hun.

Dan wanders off with Ying Ki and they both swim over to Ching's ship. Dan and Ching notice that seems to have no crew, and Ki says this will make it easier to kill her. As Dan tries to talk Ki out of killing Ching she appears and holds her sword at Dan's throat. Moments later Dan and Ki are hanging upside over the ship's deck. Ching asks them why she shouldn't kill them and Dan suggests as she has no crew they could do it. Ching needs to get the lost treasure and so agrees that if she spares they lives they crew the shuip for her.

But even with a crew Ching has trouble navigating. None of the equipment is working, and when she tries to navigate using celestial bodies they all seem to move. Ki says this is due to Ching unleashing power from the statue. Dan asks Ching why she needs the treasure, and she reveals that her crew have all been taken hostage and she has to pay the ransom or they will all die - including her two young sons. When the Hua-Shen appears Ching tells Ki and Dan to man the cannons.

The Doctor wants to have a word with Ching and to get Ching on-side the Doctor takes Yaz in the TARDIS to find the treasure of the Flor de la Mar. The TARDIS materialises aboard a ship in 1533. A they sneak out onto the deck it appears as though there is a mutiny, but it becomes clear that Ji-Hun is throwing the crew off the ship.

Moments later a Sea-Devil emerges from green mist, and Ji-Hun offers the ship to it. The Sea-Devil doesn't honour the agreement with Ji-Hun, and it summons a huge sea monster, the Hua-Shen, to destroy the ship. Before the ship goes down the Doctor and Yaz rush back to the TARDIS. The Doctor takes the TARDIS back to 1807 to the location of Ji-Hun's ship: at the bottom of the ocean. Only something is missing: there's no ship.

The Doctor scans the ocean floor with the sonic screwdriver as the floor cracks and disappears - leaving the TARDIS floating in the ocean. The Doctor closes the TARDIS doors just in time as the Hua-Shen bites the TARDIS and pulls it further down into the ocean. When the Doctor opens the TARDIS doors, which is lying sideways, she and Yaz find themselves in a green lit Sea-Devil base. When the Doctor mentions she is looking for Ji-Hun the Sea Devil becomes curious, the Doctor is more curious about the tecnological equipment in the ship - including a current regulator.

The Doctor tells the Sea-Devil that she had met them in the future - although by then they were honourable and risk-averse - the Sea Devil tells the Doctor that they have made Ji-Hun's ship they own and leads the Doctor and Yaz into a cavern where the ship that had attacked the village is hovering. The Sea-Devil then demands the Doctor tells it where the Keystone is. Yaz is about to say they don't know what the Keystone is, but the Doctor interupts and tells the Sea-Devil she want's to see the ship first.

When Yaz asks about Ji-Hun the Sea Devil operates a terminal and a compartment opens showing Ji-Hun trapped inside a force field. When the Sea-Devil leaves the Doctor and Yaz alone they speak to Ji-Hun. He tells them that he wasn't working with the Sea-Devil, and that he forced his men off the ship in the hope they would survive. When he asks if the Keystone is safe he explains that the ship was carrying the largest part of the treasure and that the remaining part, the Keystone, would unleash infinite power.

When the Sea-Devil returns it says it knows the Doctor does not have the Keystone as the Hua-Shen has located it on the surface. As the Sea-Devil prepares to kill the Doctor she activates the control that takes the ship to the surface.

On board Ching's ship Ching, Dan, and Ki, watch as Ji-Hun's ship appears floating above the water. With a cry of "Geronimo" the Doctor, Yaz, and Ji-Hun, appear on deck. After introductions the Doctor asks Ching for the keystone. When Ji-Hun describes it, and says it can glow orange, a jewel on a necklace around Ki's neck glows, and the Sea-Devil appears on deck. As the Sea-Devil takes the Keystone the Doctor realises what power it contains and leads everyone back to Ji-Hun's ship.

With the device the Sea-Devils could flip the magnetic poles of Earth causing chaos, melting the ice caps, and flooding the Earth allowing the Sea-Devils to reclaim what was once theirs. With more Sea-Devils approaching the ship the Doctor, along with Ching, Ki, Ji-Hun, and Dan, fight them off and the Doctor disarms the Chief Sea-Devil before Ki, much to the Doctor's disgust, kills it.

With the Chief Sea-Devil out of the way the Doctor and Yaz head off to stop the the Keystone whilst Ji-Hun, Ching, Ki, and Dan, are left to contend with the Sea-Devils. The Doctor sets Ji-Hun's ship to implode. Someone needs to stay behind to hold cabling together, and Ji-Hun stays whilst the Doctor gets Yax, Can, Ki, and Ching, back to Ching's ship, along with enough treasure to pay the ransom for Ching's crew.