Showrunner Steven Moffat is once again leading the way on the writing front, penning four episodes by himself for series 9 - the first two and the last two - and also co-writing one alongside Jamie Mathieson, who wrote last year's Mummy on the Orient Express and Flatline. Mark Gatiss has written his usual episode, which will presumably be the really-quite-scary one. Other familiar faces include Peter Harness, who wrote series 8's Kill the Moon, and Toby Whitehouse, who returns to the series after a year break, having written episodes in all of Moffat's series before the last one. The new additions to the writing team this series are Sarah Dollard, who has mostly written for Neighbours, and Catherine Tregenna, who wrote for Torchwood back in season 1 and 2 (but unfortunately probably won't mean a return for Captain Jack).