Rachel is still reeling from the news that the Earth is secretly under attack by parasitic aliens known as the Yeerks. And that she and her friends - five kids who, purely by chance, stumbled onto a downed spacecraft and were given the power to morph into any animal they touch - are the planet's only defense. But Rachel's always been something of a daredevil. So when it's suggested that they infiltrate the home of their assistant principal, Mr. Chapman,...

Jake finds a Web site devoted to the Yeerks that could be a trap so they must move quickly.

"Tobias has pretty much gotten used to his life. He's a red tailed hawk with the mind of a kid. It was pretty weird when he first got trapped in morph. But now it's almost okay... Now Tobias is about to make a very special choice. A choice that the other Animorphs and Ax know nothing about. And it could mean the difference between being a hawk... and being human..."--Cover.

Marco never wanted to be an Animorph. He didn't want the ability to change into any animal he touches. And he certainly didn't want to be one of a handful of kids that are the planet's only defense against a secret alien army. His friends know why he feels the way he does. He's worried about his dad - the only family Marco has left. If anything happens to him, his father will be alone. But something big is about to change for Marco. Something that...

Cassie acquires the mind of Aldrea, daughter of Seerow, Andalite Prince, as well as her memory, persona, secrets, and an abundance of valuable information that will help the Animorphs.

David and the others search for Senna in EverWorld. They don't know if she's in EverWorld or even if she is alive.

Ax and the Animorphs have a huge problem when they decide to morph mosquitos to slip by some Yeerks. They end up stuck in Zero-space with no idea how they got there, no way to get back to Earth... and no oxygen.