Jorgan Pace, adopted son of Fleet medics, wants to be an engineer on a starship. Going to the Fleet Academy is far in the future. He's only ten years old.

When his family is transferred to the Defender, they meet two other families also traveling to their new assignment. Despite the short voyage, by the time they reach the Defender Jorgan has made a new friend and earned several enemies. When the bullies play a nasty trick on him, he uses his engineering skills to pay them back, which disappoints his parents. Then, when another nasty trick threatens to get Jorgan in even more trouble, it turns into an opportunity to put his skills to good use.

Problems with another boy's mechanical legs present a mystery for the new friends to solve together, and brings them face-to-face with a creature out of legend. At the end of their journey to their new home, Jorgan's efforts earn him a chance to meet his hero, Chief Engineer Jasper Lore of the Defender.