Vorsad, a professor at the university of London, come to check on his old house when he sees a bright purple light from a window which he investigates. But little does he know that aliens have arrived to use his scienctific equitment to clone Earth to start their own race again. However the noise of the universe fills the house with sound to which steps out Matt, David and Gwen, they are quiet unsure why the TARDIS has brought them here at the start but when they find out that Sontaran’s are cloning the world, the soon understand...