The new 'Doctor Who' Christmas special trailer reveals more than you think

In a pivotal Doctor Who special that aired over the weekend, we saw the 15th Doctor (Ncuti Gatwa) leave his 14th incarnation (David Tennant) and companion Donna Noble (Catherine Tate) for new adventures. Now we know exactly how he encounters his next human companion, Ruby Sunday (Millie Gibson).

In a brand new Disney+ trailer for the Christmas Day special "The Church on Ruby Road," Gatwa and Gibson meet in a nightclub at Christmas where the Doctor is dancing (yes, old school fans, the Doctor dances) in a vest and fetching tartan kilt.

Ruby Sunday accidentally knocks her drink off a table. The Doctor retrieves it. They lock eyes. And another excellent adventure through all of time and space has begun.

"Health and safety, gin and tonic division," the Doctor says, according to dialogue published in Doctor Who Magazine. "Can I ask, do you get that a lot? Knocking things over?"

"I'm just clumsy," Sunday replies. The Doctor responds that it's no accident, but part of a greater mystery: "It's worse than that."

"What is a coincidence but a form of accident?" the Doctor adds in the Disney+ trailer. "Two things bumping together unexpectedly" — like the Doctor and Ruby Sunday.

New Christmas special details revealed

The Disney+ trailer, released Monday exclusively on Mashable, goes further into the forthcoming story than the BBC trailer, released Saturday after the final 60th anniversary special, 'The Giggle.'

Controversially, that episode showed Gatwa literally emerging from Tennant in a new-to-the-show process called "bi-generation" that let Tennant's Doctor survive — as opposed to being replaced in the regeneration fans were expecting.

How is returning showrunner Russell T Davies following that audacious move? With a special that both feels like a traditional Christmas "Who" turned up to 11, and one that feels utterly fresh for Gatwa's groundbreaking tenure in the TARDIS.

The Rwandan-Scottish actor, 31, is the first Doctor to have been born in the 1990s, after the classic series (1963 to 1987) was cancelled but before Davies revived the show in 2005.

And because Davies likes to focus on his companions' families — remember Rose and the rest of the Tylers? — this Disney+ trailer offers the first glimpse of Ruby's mother, Carla Sunday (Michelle Greenridge). Still to be revealed is her grandmother, Cherry (Angela Wynter). And yes, crucially, Ruby is adopted.

That may become relevant in a story that is all about a race of goblins in a flying clipper ship that steals babies. The goblin's baby-eating song featured in the episode was also released Monday, along with a lyric video. In the Disney+ trailer, we also see the Doctor in the snow with a baby in his arms.

A sonic screwdriver unlike any before it

Also in the Doctor's hands: a larger sonic screwdriver, in the shape of a TV remote. In another video, Gatwa reveals that the tech upgrade includes a kind of "USB port" that allows the Sonic to connect to any other device. It also proudly bears a Gallifreyan translation of a Rwandan phrase: "the sharpness of the tongue defeats the sharpness of the warrior."

There have been few better summaries of what Doctor Who always was, and still is, all about. The sharpness of the Doctor's mind will also be required to figure out why he and Ruby Sunday happened to meet in that nightclub. Is the "coincidence" part of a nebulous plot, as when the eleventh Doctor met Clara Oswald courtesy of a mystery frenemy?

We'll find out when Doctor Who returns on Disney+, and the BBC in the UK, on Christmas Day.