Mark is left behind on Mars. Everyone thinks he is dead. He needs to find a way to get back to earth. He is doomed.
Mark figures out a way to plant potatoes and grow them with martian soil and human fertilizer. He makes his own water with hydrogen and oxygen. This allows him to last until the next Mars Mission
NASA officials watch Mark through satellite images but cannot communicate. Mark remembers that a probe had crash landed not far from where is lives. He goes on a mission, gets the probe, fixes it up and gets communication with NASA.
Marks fellow astronauts turn their ship around and Mark drives to a ship that is prepped and ready for take off on Mars. Mark needs to launch off Mars and land inside his friends space ship. Mark barely makes it aboard and he is saved.
Mark broke 2 ribs and his being cared for by his friends. He goes through x-rays and gets bandages. He smells really bad and his whole body aches but he is happy.
Everyone helped save Mark. Millions of dollars went into getting him back home. After 211 days on the space ship that would take him back to earth he makes it.