Jake, Marco, and Ax went to the theater to watch a movie, where Ax got so obsessed with popcorn that he crawled on the ground frantically looking for more. When stared back at the screen, the picture displayed a reminder of his home, and he must contact his home world.
Although Ax has been fighting side by side with the Animorphs for as long as he's been on Earth, he's always seemed distant, not quite trusting of human beings.
They brought him over to Marco's house, where he went crazy over the spicy food that Marco's father made him eat. Ax then breaks into a satellite company, and modifies the computers so he can phone home. Jake and Marco also sneaked in by morphing lizards.
When he does, his father picks up and Ax places the dishonor of giving a lower species Andalite technology on Elfangor, he takes on the burden himself, disobeying the law of Seerow's Kindness. Marco's father works at the local observatory, and Ax must confiscate the space technology he accidently invented on the primitive computer. While doing so, a human-Controller is spying on him. The Controller wants to use Ax to destroy Visser Three; Ax is the meantime was just about to do so alone. The Controller gives him a heads-up when the Visser will not be in the Andalite body and be weak.
Ax goes to assassinate the Visser while vulnerable, but Hork-Bajir Controllers and armed human-Controllers challenge him. Jake and the other Animorphs come to his rescue. In the end, Ax realizes that the Animorphs are his friends and he should not keep secrets from them.