BBC Studios/Bad Wolf/James PardonHumanity faces threats from across space and time in Doctor Who, but in its latest spin-off, trouble lurks deep underwater.
The War Between the Land and the Sea follows Barclay, played by Russell Tovey, as he’s plucked from obscurity to become humanity’s ambassador when the Sea Devils rise to the surface.
It’s 53 years since the ancient species’ on-screen debut, and three years since they were seen battling Jodie Whittaker’s Doctor aboard a pirate ship.
Despite the aquatic antagonists’ long history, the new series’ cast and crew insist the five-part story, set within Doctor Who’s universe, stands alone.
And, they tease, it has plenty to say about the state of the real world today.
“It’s a really beautiful, brilliant, compelling show,” Russell Tovey tells BBC Newsbeat.
“You can watch Doctor Who, or you can never have seen it.”
BBC Studios/Bad Wolf/Alistair HeapThe villains have set their sights on seizing something a little bigger – Earth itself – led by Gugu Mbatha-Raw’s Salt.
The actress appeared in Doctor Who during the David Tennant era as Tish, sister of the Doctor’s companion Martha Jones.
She went on to have roles in high-profile shows including Black Mirror, Loki and The Morning Show.
And you might not immediately recognise her on her return to the Whoniverse, thanks to her transformation into the leader of the Sea Devils.
“The prosthetics are just so detailed,” Gugu tells Newsbeat.
Not everyone on set was a fan, though.
“But Russell’s dog Rocky wasn’t into it,” she says.
“I’d forget I was dressed as Salt, he’d growl and I’d think: ‘Oh yeah, I’m blue’.”
“The War Between is a wild, epic, thrilling adventure,” says Gugu.
“It has so many compelling messages about the world we’re living in and what we can do about it.”
BBC Studios/Bad Wolf/James PardonAs the title of the series suggests, one of its themes is humanity’s relationship with the sea.
In one extraordinary action sequence, the Sea Devils weaponise the vast quantity of plastic dumped in “their” ocean and throw it back.
All of it.
All at once.
Russell Tovey says that’s thanks to the work of the show’s set designers, as well as its special effects team.
“You will watch this thinking a lot of money’s been spent on green screen,” the 44-year-old says.
“But there were set-builds that were unbelievable. It was so immersive.”
The spin-off is co-written and executive produced by Russell T Davies, who led Doctor Who’s original revival in 2005.
The Bafta-winner became its showrunner again with Ncuti Gatwa as its lead 16 years later.
Its latest reboot was partly funded by Disney+ after the streaming giant agreed to try and fly the Tardis to new heights.
But The War Between, made under the same deal, draws the Whoniverse’s dabble with Disney and its spending power to a close.
“The BBC’s never had the budget to make a proper sequel to the original Sea Devils story,” Davies tells Newsbeat.
“These big pictures are gorgeous. However, Gugu and Russell Tovey are the heart of it.
“It’s all about the emotion at the centre and that’s what will get you watching.”
It’s a first look at the Whoniverse since Ncuti’s Doctor appeared to regenerate into former companion Rose Tyler, played by Billie Piper.
In October, the BBC said it remained “fully committed” to Doctor Who, with a Christmas special set for 2026.
“We haven’t even started work on it yet,” says Davies.
“I know what happens, but I better write it down soon in case I get run over by a bus.”
Davies tells Newsbeat he shared his plan with BBC bosses, leaving them “with jaws agape, loving it”.
But any fan hoping to learn more about the Doctor’s fate will have to wait.
Humanity’s more pressing concern is to defend itself from the Sea Devils.
“Will we survive?” he teases, with a grin.
The War Between the Land and the Sea’s first two episodes drop on BBC iPlayer and BBC One on Sunday 7 December, before premiering on Disney+ around the world in early 2026.
