The Red Planet

We have all heard of Mars, and their inhabitants have heard of us. Once The 5th incarnation of The Doctor stumbles upon The Red Planet after accidently falling into a Time Corridor, he puts his companions in one of the most dangerous adventures yet. With one of them stuck on the grounds can the other two get help before The Doctor faces a threat from both, the past and present? With Mars' future at risk, and his friends in jeapordy, which path will The Doctor take?