Terry has been selected for the greatest tractor adventure in history: to go to Mars with the first manned mission.

When the crew arrives on the red planet they find that the Martians are not friendly and that they cannot communicate their peaceful intentions to them. The crew has to flee back to their spacecraft. Fortunately, Terry finds that he can understand the Martian language, so he is sent to the surface of the planet. When he reaches the Martian city Terry finds that the creatures like him and he introduces the crew to his new Martian friends.

Things are going well when a huge asteroid is detected. It is headed straight towards the Martian city. The only way to save the Martian civilization is for Terry to go into space on the first “space crawl” to deflect the asteroid.

The asteroid hits Terry and his is almost killed. He goes tumbling off into space. Will the crew of the space ship be able to save Terry?