As we approach the halfway point in the series, Doctor Who’s getting religious – as well as bringing back one of the series’ greatest villains… 

What’s it called?

Episode 6 will be called Extremis, joining an unusually large collection of pithy titles this year including Smile, Oxygen, Thin Ice and Knock Knock.

When is it on TV? 

Barring unforeseen delays, the episode will air on the evening of Saturday 20th May.

What happens in it?

The Doctor and Bill are called to help The Vatican, only for villain Missy (Michelle Gomez) to get tangled up in their adventures. 

As series showrunner Steven Moffat exclusively told us:

“They read The Veritas – and chose hell.”

In the Haereticum (the Vatican’s secret library of blasphemy) there is an ancient book known only as The Veritas. Throughout history, anyone who has ever read it has immediately taken their own life. Now a new translation is online, and the danger is spreading. The Vatican appeals to the Doctor. Will he read The Veritas? But can even the Doctor survive the ultimate truth?

Who’s in it?

Alongside Peter Capaldi’s Doctor, Pearl Mackie’s Bill and Michelle Gomez’s Missy, guest stars will include Laurent Maurel as Nicolas and Corrado Invernizzi as Cardinal Angelo.

Who’s written it?

Head writer Steven Moffat has penned this episode, which will be directed by Daniel Nettheim.

Who are the baddies? 

Some terrifying zombie-like creatures known currently as the Monks (pictured), though Moffat has recently hinted that may not be their real name. 

“We’ve got a new enemy, which I won’t talk too much about but we call them “The Monks” – though that’s not really their name,” he said. 

Anything else?

Since the announcement of Gomez’s return as the female regeneration of The Master, it’s been revealed that John Simm’s previous incarnation will also be appearing in the new series.

While Simm is likely to be cropping up later in the series rather than in this week's story, it wouldn’t be surprising to find a few hints about his upcoming appearance in this first Missy-featuring episode.