First broadcast: Saturday 28th June 2008 & Saturday 5th July 2008 The darkness was coming in the Series 4 finale but luckily the Tenth Doctor and his coveted Children of Time were on hand to save the day. Oh, and the entire universe from its untimely destruction, of course. No pressure, then! Speaking of hands, a very handy spare one got a certain titular Time Lord out of a rather sticky situation when he was exterminated by a Dalek who managed to completely ruin the moment and destroy The Reunion We'd All Been Waiting For in the short space of two seconds. The almighty twist led to one of the most shocking cliffhangers in Doctor Who history and the nation sat with baited breath as their hero began to regenerate before their very eyes. Was it really the end?! Well, no, as it turns out, because this is where everybody's favourite temp from Chiswick, Donna Noble, and her conveniently executed metacrisis come in. The inclusion of another Doctor - albeit a half human one - added to the sheer eccentricity of the ensuing drama but it led to one of NuWho's defining moments when the Doctor and his companions flew planet Earth to safety and away from the trepidatious threat of the Daleks and their demonic leader, Davros. So dramatic. So good. So Russell T Davies.