Doctor Who returns to BBC One this weekend with a new episode, ‘Extremis’, written by Steven Moffat himself.

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?

Pre-order the new season on DVD on Amazon here.

Pre-order the new season on Blu-ray on Amazon here.

‘Oxygen’ airs at 7.15pm on Saturday 13 May on BBC One.

Here are 10 spoiler-free lines of dialogue from the episode…

“Okay, so what’s the title?”

“Of course there’s Wi-Fi – it’s a library.”

“Nardole, are you secretly a badass?”

“This technology is precisely calibrated.”

“Don’t do anything I wouldn’t do.”

“Impossible. Quite impossible.”

“You’d be wizard at writing Christmas crackers, you two.”

“Who are you? What are you doing here? Speak! Speak to me!”

“In darkness we are revealed.”

“Leaky roof is it?”

Who do you think says each line? And what are they talking about? Let us know below…