Doctor Who: Legend of the Sea Devils' 8 biggest questions

Starting with a quick history lesson…

Who was the real Madame Ching?

Yes, Madame Ching (aka Zheng Yi Zhao, among other names) was a real historical pirate, and plenty of what we hear in the episode is true. She was more or less the most successful pirate ever, in fact, commanding a vast fleet of 3-400 pirate ships with 20,000-60,000 men at the height of her power.

Born in 1775, she married a pirate called Zheng Yi when she was 26, and upon his death took over his pirate confederation. To learn more about her life, you can check out our guide to the real history of this episode of Doctor Who elsewhere on RadioTimes.com. - Huw Fullerton

What was the Sea Devils' plan?

In case you tuned out or got a little wrapped up in other parts of the episode, here’s what the Sea Devils were up to in this episode. First off, their boss had been turned into a statue by the magic keystone. That was undone accidentally by Madame Ching (Crystal Yu), and then the other Sea Devils woke up from their centuries-long catnap to pick up their head honcho.

Their next move? Get their hands on the keystone, which was… somewhere. After they found it, they could use its powers and their advanced technology to… well, the Doctor (Jodie Whittaker) probably explained it best.

"You’re trying to flip the Earth’s geomagnetic poles – north to south, south to north, longitude to latitude. That’s why even the stars feel like they’re moving.

"You wanna create chaos. Melt the ice. Shift the current. Change the pressure, until the whole Earth is flooded."

"We are reclaiming what was ours – it is our right, and it is our time," Marsissus (Craige Els) replies.

In other words, the Sea Devils are looking to wipe out the "land-crawlers" (aka you, me and the rest of the human race) and take back their planet. Presumably this was also their plan in the 1500s before it was derailed by Ji-Hun.

Not sure how their relatives the Silurians would feel about being drowned out, but hey – it’s every monster from the dawn of time for themselves. - HF

What was the keystone and what are its powers?

Much of Legend of the Sea Devils concerns various characters hunting for a MacGuffin known as “the keystone”, which was uncovered by Ji-Hun as part of the lost treasure of the Flor de la Mar. Ji-Hun guarded the keystone until the Sea Devils came calling in 1533, sending it off-ship with one of his crew – and that crew member’s descendant is Ying Ki (Marlowe Chan-Reeves), who still holds the item in 1807, 274 years later.

But what actually is the keystone, and what are its abilities? Ji-Hun calls it a “formidable gem with infinite powers”, telling the Doctor and Yaz (Mandip Gill). “Hold the key stone and you may change the course of the world – freeze life and time, transport matter.” (It can also be used to "used to entomb aggressors”, which is how that one Sea Devil ended up as a living statue.)

The keystone, it transpires, is actually Sea Devil technology (or as Ji-Hun puts it, “the vast lost power of a demon race from beneath our waters”) – a crystal that, in conjunction with the Sea Devils’ other devices, can flip the Earth’s geomagnetic poles, allowing the aquatic villains to “melt the ice, shift the current, change the pressure until the whole Earth is flooded.”

How exactly it does this, what the limits of its power might be, and for what purpose the Sea Devils designed the keystone in the first place – presuming it was created, and not discovered – is never made entirely clear. Let’s just say it’s a magic gem and be done with it. - Morgan Jeffery

When did the Sea Devils get so high-tech?

Speaking of, where and when did the Sea Devils pick up all their latest high-tech gear?

The versions we saw in 1972’s The Sea Devils and 1984’s Warriors of the Deep weren’t exactly cavemen – despite, y’know, actually coming from a time before cavemen – with laser weapons to fend off enemies and transport capsules to move about, but the breed here certainly appear to be a cut above, with a high-tech headquarters, a flying ship (adapted from a human craft to “instil fear in the land-crawlers”) and the power to teleport.

It’s important to remember, of course, that the Sea Devils / Silurians are an entire race of creatures, and much like the human race, could well be divided into different ethnicities and different settlements, each with its own culture. This would explain the difference in not just technology but clothing between these Sea Devils and ones we’ve glimpsed in the past – though we’ll be honest, we sort of miss the fishing net outfits. - MJ

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Was the sea monster a Myrka?

When fans caught sight of an enormous ocean-dwelling monster bearing down on Madame Ching’s ship in a teaser for Legend of the Sea Devils, they immediately began speculating as to whether said sea creature might be a Myrka.

For those of you not in the know, the Myrka appeared in the 1984 serial Warriors of the Deep, the only story to date to feature both the Sea Devils and their land-dwelling cousins the Silurians. One of the least convincing creatures in Doctor Who’s long run, the Myrka was ostensibly a genetically-modified dinosaur-type creature, unleashed by the Silurians in times of war – but on-screen, it looked more like a pantomime horse.

Spin-off media has since sought to restore the Myrka’s reputation, with books, comic strips and audio plays all able to depict it as a rather more fearsome foe – in fact, the Big Finish play Bloodtide from 2001 even sees an enormous Myrka emerge from the ocean to attack a ship.

The creature seen in Legend of the Sea Devils, though, is referred to as the “Hua-Shen” and is considered a mythical beast by Madame Ching and Ying Ki – this has some basis in real myth, with the "shen" or "chen" being a sea monster in Chinese mythology, an “aquatic dragon” with the power to change its shape.

It’s probable, then, that this is a different creature entirely to the Myrka – after all, in 1970’s Doctor Who and the Silurians, the eponymous monsters used another sort of dinosaur-type creature, resembling a T-Rex, as their guard dog. It seems the Silurians and the Sea Devils have a veritable zoo of these beasts at their disposal. - MJ

How did Ji-Hun survive?

Speaking of Sea Devil tech, if you’re a little unclear as to how Ji-Hun (Arthur Lee) was kept perfectly preserved for almost three centuries, it’s worth remembering that the Silurians and Sea Devils only survived themselves thanks to advanced cryogenic technology – millions of years ago, they used this technology to enter a form of stasis when they feared the Earth was in danger, with humanity only emerging as the dominant species on the planet when their reptilian forebears laid dormant for longer than expected due to a technical snafu.

Presumably, a tweaked version of this stasis tech can also be used to hold prisoners like Ji-Hun hostage, held like a fly in amber… who knows how many other figures from history the Sea Devils might have locked up somewhere, waiting to emerge into a bewildering future? - MJ

Can you flood the TARDIS?

The Doctor takes her ship to the very depths of the ocean in an effort to uncover the wreck of a pirate ship once captained by Ji-Hun, all part of a larger plan to recover the lost treasure of the Flor de la Mar, in order to bargain with pirate queen Madame Ching and learn more of what she knows about the Sea Devil’s plot (Do try and keep up).

Yaz expects the TARDIS to flood when the Doctor opens its doors underwater – but the Time Lord explains that the craft is surrounded by a shield which keeps them safe in an oxygen bubble (and also, quite possibly, protects their transport from being crushed by the enormous amounts of pressure that exist on the ocean floor).

Either this is a new(-ish) innovation or the Doctor is able to disable it at will, since back in the 1981 serial Logopolis, the Fourth Doctor (Tom Baker) planned to flood the TARDIS by materialising underwater and opening the doors, in a rather unorthodox effort to eject the invading Master (Anthony Ainley) from the ship.

We never got to find out if the Doctor’s cockamamie scheme would work, since he missed his mark and landed on a ship instead of beneath the waves – but given the TARDIS interior is apparently almost limitless, would it even be physically possible to totally fill it with water?

Never say we don’t ask the big questions here at RadioTimes.com. - MJ

Did Dan murder a bunch of Sea Devils?

We knew he was pretty handy with a cast-iron skillet, but who would have expected Dan to be such a cold-blooded warrior?

Just moments after the Doctor decried the death of the Sea Devils’ leader, John Bishop’s plucky plasterer grabbed a sword and sliced about a half-dozen of them down no problem. No recriminations, no guilt, (apparently) no blood – Dan just got a congrats from Ji-Hun and they left the cooling bodies on the floors behind them.

Maybe all the fan conversations about Evil Dan had some bearing after all? You can’t deny it – he’s good at this… - HF

Is this how or why Dan leaves the TARDIS?

At this stage, it seems pretty certain that we’ll be getting a big shake-up with the Doctor Who cast, with Mandip Gill and John Bishop expected to leave the show alongside Whittaker and showrunner Chris Chibnall this autumn. Really, the only question is… how will they go?

And we may have had our first clue in Legend of the Sea Devils. Towards the end of the episode, Dan takes a call from his former flame Diane (Nadia Albina) who got in a huff with him for, er, not getting captured by the same aliens as her during series 13 (we’re still a little confused on that point). Anyway, it appears she might be offering a rapprochement, and Dan seems keen to see her again by the story’s close (though hopefully, he’ll change his outfit before he sees her).

"Are you gonna be back here any time soon?" she asks him, his reply left unsaid. Maybe this is how Dan leaves the TARDIS – he goes back to his life in Liverpool to be with Diane. Maybe that’s where the trio will head next, dropping him off in present-day England. Stranger things have happened.

As for how or why Yaz would leave, though? That’s a bit more complicated. - HF

What will happen with the Doctor and Yaz?

Legend of the Sea Devils moved things along a little for the Doctor and Yaz, with the Doctor admitting that she shared Yaz’s feelings but couldn’t act on them for various reasons (implied to be because of the Doctor’s own foretold death).

Now, with just one episode to go before Jodie Whittaker’s regeneration, it’s hard to see how this story could be resolved – because we know Mandip Gill is also leaving the show. As we know her now, it seems impossible to imagine Yaz abandoning the Doctor, let alone at a time when she’s most vulnerable. So what’s going to change?

It seems unlikely they’d kill Yaz off – there are negative tropes around the death of queer characters that the BBC would be keen to avoid, and it’d be a bit of a downbeat ending before the Doctor’s regeneration.

More likely, it seems like Yaz will be forced to abandon her time-travelling life for some reason. Catherine Tate’s Donna had to have her memories wiped for her own protection – maybe we could see something similar here. Maybe some foe of the Doctor’s will try to use Yaz against the Doctor, doing something to her that will prevent her following the Doctor round the universe any more.

Perhaps the Doctor will realise the dangers to Yaz herself. We know the Doctor will face great challenges in the centenary/regeneration episode, and she might decide Yaz is better off without that constant danger.

Or maybe it’d be Yaz’s choice. We’ve seen Freema Agyeman’s Martha Jones leave the TARDIS life after the Doctor didn’t requite her romantic feelings, so perhaps Yaz will decide she’s better off making a normal life with someone else. It could also be that Yaz isn’t such a fan of the next incarnation of the Doctor post-regeneration, and can’t imagine a life with someone who isn’t "her" Doctor.

However it’s achieved, it’ll be fascinating to watch the whole thing play out. With just one episode to wrap this whole storyline up, we don’t envy Chris Chibnall trying to thread that needle. - HF

Read more about Doctor Who:

• Doctor Who: Legend of the Sea Devils podcast review
• Doctor Who's Legend of the Sea Devils ends with regeneration hint
• Doctor Who finally addressed the River Song elephant in the TARDIS

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