A happy return to normal space is interrupted by a missile hitting the TARDIS. Was it an accident or was it deliberate? Does it have anything to do strange goings on in the English countryside? Will an old friend be able to shed some light on the subject? This week Paddy and Tricia discuss a game of cat and mouse between the TARDIS crew and the head of a shady corporation, which is spearheading an extraterrestrial Invasion.