The TARDIS arrives on Coldstar, a vast freezer satellite, packed with supplies to feed a colony world. But there are cracks in the ice, and something scuttles under the floors. Soon, Rose and the Doctor encounter robots, space pirates and... refuse collectors. As Coldstar's tunnels begin to melt, an even greater threat stirs within. An old enemy of the Doctor puts a plan into action - a plan for retribution. Nobody's vengeance is colder than an Ice Warrior's.