Doctor Who boss reveals new plot details for Legend of the Sea Devils

"In our story, Madam Ching is on a mission to track down the lost treasure of the Flor de la Mar, a ship that may have been washed up in the waters around the area where we start the story," he explained.

"She unleashes a terrifying evil that the Doctor has to help everyone deal with."

It was co-writer Ella Road's suggestion to include the 19th-century pirate leader Zheng Yi Sao, aka Madam Ching (played in the episode by Crystal Yu) – who is also a real character from history.

“She features in lots of stories throughout history, but her actual character is quite slippery and hard to pin down," Road said. "So I said, ‘What about her?’"

The official synopsis provided by the BBC for the episode reads: "This episode finds the Doctor (Jodie Whittaker), Yaz (Mandip Gill) and Dan (John Bishop) in 19th century China, where a small coastal village is under threat – from both the fearsome pirate queen Madame Ching (Crystal Yu) and a monstrous alien force which she unwittingly unleashes."

It continues: "Will the Doctor, Yaz and Dan emerge from this swashbuckling battle with the Sea Devils to save the planet?"

This weekend, the first trailer for the episode was released, teasing some new tension between the Doctor and Yaz and hinting at an epic adventure that includes a hovering galleon, sci-fi sword fights and some sort of deep-sea monster.

It will be Jodie Whittaker's penultimate episode as the Doctor, and director Haolu Wang previously teased it will be her "last chance to have fun" in the role.

Read more: Mandip Gill teases Thasmin development in Doctor Who’s next special

Doctor Who: Legend of the Sea Devils comes to BBC One and BBC iPlayer on Sunday 17th April. For more, check out our dedicated Sci-Fi page or our full TV Guide.

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