In the 50th nniversary story The Day of the Doctor, the Doctor's home planet of Gallifrey was frozen in an instant of time, effectively causing it to drop out of the regular flow of time in the universe and be saved from imminent destruction at the protuberances of the Daleks. Viewers know this because the fate of Gallifrey is very clearly explained in that episode. There's no room left for doubt, and there's no possibility allowed for misunderstanding. Except, in the following episode, The Time of the Doctor, viewers are told Gallifrey was actually trapped in another dimension or something (it's a bit vague). Presumably, this detail was changed so the Time Lords on Gallifrey could intercede in the Doctor's plight on the planet Christmas and offer him a new regenerative cycle. But no explanation for the change in Gallifrey's condition was offered. Plainly, the producers thought, "No one will notice, right?", but, at least if online forums are any guide, pretty much every last viewer did notice, and they roundly mocked the show for immediately contradicting an established "fact" without so much as a by-your-leave. Don't worry, though, because if the finale of Series 8, Death in Heaven, is anything to go by, the Doctor is now searching for Gallifrey in regular space, simply by flying to coordinates supplied by Missy, opening the TARDIS doors, and taking a quick look. Frozen moment of time, another dimension... nah, the Doctor will find Gallifrey simply by checking under the broccoli on his dinner plate. The whole "Gallifrey is frozen in time" plot point was brushed under the carpet because of its inconvenience to subsequent stories. After all, frozen Time Lords can't act as deus ex machina plot devices. What makes the ret-conning hard to swallow (other than its breathtaking rapidity and the sheer disrespect to viewers) is the fact that the same writer wrote the original cause of Gallifrey's disappearance and the retroactively inserted reason. In a sense, changing a plot point is better than simply ignoring that the point was ever made. The classic example of a plot point that was promptly deleted wholesale from continuity has to be the Doctor being "half human on mother's side", to quote the 1996 TV movie. This revelation was excised because the creators of the revived show simply... didn't care for it. Only a tiny handful of fans objected.
Mike has lived in the UK, Japan and the USA. Currently, he is based in Iowa with his wife and 2 young children. After working for many years as a writer and editor for a large corporation, he is now a freelancer. He has been fortunate enough to contribute to many books on Doctor Who over the last 20 years and is now concentrating on original sci-fi & fantasy short stories, with recent sales including Flame Tree, Uffda, and The Martian Wave. Also, look for his contribution on Blake's 7 to "You and Who Else", a charity anthology to be released later this year.
You can find him on Tumblr at https://www.tumblr.com/blog/culttvmike