The Doctor, Romana and newly elected President Sheridan Moorkurk take on the all-consuming powers of business tycoon Cuthbert and his vast Conglomerate. But the situation goes beyond a struggle for political power. Cuthbert is intent on revenge on creatures he feels have attacked his interests. But when his revenge looks like it's leading to interspecies war, the Doctor knows the stakes couldn't be higher. The Laan are on the move. Is it too late to prevent the destruction of all life on Earth?

Directed by Nicholas Briggs.