But as the Doctor informs Group Captain Gilmore, the hostile agressor which has already killed one of his men is not remotely human. For London in 1963 is to be the alloted place and time for a further encounter between the Doctor and his most feared enemy - the Daleks. Accompanied by a streetwise teenager from the 1980's called Ace, the Doctor must prevent the Daleks from capturing the Hand of Omega - the key to control of time. But for this crucial encounter the Daleks pose a doubly sinister threat, for the Hand of Omega is sought by two opposed Dalek factions - the Renegade Daleks and the Imperial Daleks. Why have the Daleks splintered into these two factions and what, or who, is controlling them? These are the questions the Doctor must solve if he is to retain control of time itself...