An Earth rescue expedition goes to Mars to rescue an earlier mission and finds only one survivor, the expedition leader Col. Carruthers. He is under arrest and will face a court-martial on his arrival back on Earth. No one believes his fantastic story of a Martian monster that methodically killed all of the members of his crew, one by one, until only he was left. On the return trip however, they realize the monster is on board and living on the lower decks. It begins to … mehrattack the crew who quickly become concerned about their own survival... weniger