Jack lives and works on EM-05, a steampunk space station found on a major trade route between Earth and Mars. He spends his days tarring the insides of frigates and galleons, as they stop for repairs and supplies, on their way to the distant planets of the Solar System. There are very few other children that work on EM-05 and so it can get very lonely for Jack. However, he does have one close friend, an abandoned cat named Jet, and the two of them are inseparable.
Jack and Jet find that their lives are thrown into turmoil when a gang of space pirates steals a valuable galleon. The two friends are flung into an incredible adventure and Jack is forced to devise a cunning plan to return them both to their intergalactic home.