Doctor Who (2005) 4x12

The Earth has been moved, and it's a race against time as Donna and the Doctor try to find it before the Daleks destroy everything; they head for the Shadow Proclamation and the Medusa Cascade. Meanwhile on Earth a veritable bevy of ex-companions join together to contact the Doctor and take down the Daleks. Can Captain Jack, Sarah-Jane, Martha Jones and Rose find the Doctor in time...