Army of Ghosts, the first part of the finale for Series Two of the revived show, works very much like most Doctor Who part ones. The Doctor and his companion discover something is amiss with the world and by the end of the episode they have found out that an old foe - in this case the Cybermen - is behind it. So far, so familiar. But then it pulls the rug from under our feet and reveals that there is a second alien menace at work here. The Daleks! Of course, the gambit of revealing that there is a bigger enemy working behind another has been done before. The Invasion of Time made us think that the Vardans wanted to invade Gallifrey when they were really just scouts for the Sontarans - but never with the flair of this Earth-shattering moment. Other than in playgrounds, the Daleks and Cybermen had never appeared together but this promised a match of Doctor Who's biggest bads.
