We go behind the scenes of this spine-tingling episode and hear why Rose Ayling-Ellis is having 'the best time ever!' Steffan lays camera tracks in a quarry, and we catch up with Ncuti on the beauty of acting using British Sign Language.

We uncover how Doctor Who brought Lagos to south Wales to film Inua Ellams's The Story and the Engine, and Steffan has to cater for 250 hungry people on set! Hold tight, there's a lot to discover.