Only on its third ever serial, Doctor Who was already pushing its own boundaries by turning the core concept of the show on its head. Everyone knows that during every Doctor Who episode the TARDIS lands somewhere new for the characters to explore and invariably save from trouble. However, in The Edge of Destruction, the TARDIS doesn't land at all. Played as a classic haunted house story in the TARDIS, this two-parter sees the time travellers acting strangely - even turning on each other (put those scissors down, Susan, and no one will get hurt). The reason? They think there might be something in the Ship with them (cue sting of end credits music). The Edge of Destruction is an uncommon Doctor Who episode a show usually all about its external monsters for toying with psychological horror as the crew become ever more anxious and hysterical at being trapped in the (for once) claustrophobic confines of the TARDIS. In this way, this early adventure, apart from being the only episode to be almost entirely set in the TARDIS, must be the only story to make Doctor Who's most reliable aspect the TARDIS creepy. Bigger on the inside isn't so wonderful when there might be something hiding in it...
