A little boy called George is terrified of something lurking in his bedroom cupboard…
The Doctor receives a strange distress call so powerful it has broken through the barriers of time and space…
And so begins Night Terrors (Saturday 3 September).
Written by Mark Gatiss, it's an eerie, scary tale and (as you might expect from the man who presented BBC4 documentary series A History of Horror) it employs a reliable staple of supernatural movies - toys coming to life.
"I've always been scared of dolls," Gatiss told RadioTimes.com. "And it seemed incredible that Who had never really done them. I adore the Peg Dolls - the stuff of proper nightmares!"
He's right. His creepy creations are dead-eyed, implacable and potentially terrifying.
But what do they want with young George?
Daniel Mays (last seen in Outcasts and Ashes to Ashes) plays George’s worried dad Alex, who teams up with the Doctor to find out.
Mays and Gatiss had collaborated previously on BBC3's quirky comedy thriller Funland, and Gatiss reveals how a cryptic catchphrase shared by the two during filming made its way into Night Terrors.
"'Maybe later'" became a bit of a catchphrase for me and Danny when we worked together on Funland," says Gatiss, "so I added it as a line in Night Terrors. I thought he'd be tickled - he didn't remember it at all!"
Mays probably had enough on his mind keeping up with the story. Rory and Amy find themselves miniaturised and sucked into the strange doll's house, and it’s not long before Alex and the Doctor follow them inside to meet its inhabitants...
Night Terrors is billed as a stand-alone episode of Doctor Who but we asked Gatiss if there was anything to look out for that might be significant in the future.
“It doesn't contain anything that throws forward to the rest of the season,” he told us. Before adding, enigmatically, “except for a nursery rhyme with a grim warning..."