On trial for treason, Edriss 562 explains how she infested a series of human hosts in order to spearhead the invasion of Earth by her people, the ruthless, parasitic Yeerks.
Marco, one of a group of young people who have been given the power to change into an animal in order to fight an invasion by the alien Yeerks, decides to check things out when his old friend Erek begins behaving oddly.
Andalite warrior Elfangor-Sirinial-Shamtul tells of his past adventures battling the Yeerks, ending with his final quest for the Time Matrix and the transfer of power to five human children who will later come to be known as the Animorphs.
Ax and the Animorphs become trapped in Zero-space after morphing into mosquitoes in order to slip past some Yeerks. They are rescued by an Andalite scout ship and Ax must decide whether to stay with his own people or return to earth.
Jake and the other Animorphs have discovered a Web page that discusses how to conquer the Yeerks, but before they can trust anyone they have to determine if it is for real or if it is a trap.
Rachel and her friends run into a dying alien who gives them the power to morph into any animal they touch, placing the responsibility of saving the Earth from a silent, deadly attack completely in their hands.
