Doctor Who: 10 Things You Never Knew About Series 4 Of NuWho

8. CAL's Dreamland Almost Didn't Happen

Steven Moffat's two-part story Silence in the Library and 'Forest of the Dead was a highlight in an already spectacular fourth series. But it nearly had its ending changed to make room for one of Russell T Davies' stories. In the second part of the story, Donna finds herself in a virtual reality created by CAL - the little girl whose consciousness maintains the library - which looks indistinguishable from early 21st century Britain. Donna has no memory of her time with the Doctor, but a mysterious woman convinces her that she's special and that whole alternate reality is wiped out. Two weeks later, Donna would once again find herself in an alternate world, identical to early 21st century Britain. Once again, with no memory of the Doctor and a mysterious woman who convinces her that she's special causing that reality's destruction in the Russell T Davies episode Turn Left. Only this time it was a parallel world triggered by a Time Beetle altering Donna's timeline, rather than the simulated reality created by CAL. Russell T Davies, whose responsibilities also involved script editing, spotted the similarity. At the time, the Library two-parter was set to air immediately before Davies' lead-in to the series finale, so he was worried audiences would find it repetitive. The Writer's Tale contains a lengthy email exchange between the incumbent and future showrunners to discuss the possibility of changing Donna's part in the Library conclusion. Thankfully, Davies and Moffat agreed that, while the alternate-reality ideas were similar, they were different enough in execution not to be a problem. Moffat's was an idealised reality where Donna was married with kids and a happy life, whilst Davies was a Doctor-less dystopia. Plus a later reshuffling of the episode order put Midnight in between these episodes and created a buffer between the similar storylines anyway. Sorted.