Starring Tom Baker as the Fourth Doctor. The TARDIS lands on a space station orbiting Earth in the distant future. Its seemingly deserted, but the Doctor, Sarah and Harry soon discover that they are not alone. Thousands of humans are in cryogenic sleep, and while theyve slept their Ark has been invaded. A parasitic insect race the Wirrn have taken control and threaten the very future of mankind... Digitally remastered picture and sound quality plus over 4 hours of special features!