Sheridan Moorkurk has just been elected president of Earth... but the harsh realities of who really runs the planet are just beginning to dawn on her. And what's more, she's starting to hear voices.
Meanwhile, the Doctor and Romana encounter a mass of aliens heading to Earth... Aliens who have already made the mistake of upsetting the infamous Cuthbert, all-powerful CEO of The Conglomerate, by destroying one of his space platforms.
Will the Doctor and Romana be able to avert inter-species war that will destroy all life on Earth?
Tom Baker (The Doctor), Mary Tamm (Romana), John Leeson (K9), Hayley Atwell (President Moorkurk), David Warner (Cuthbert), Toby Hadoke (Mr Dorrick), Jane Slavin (The Laan), Duncan Wisbey (General Vincent)