The Attack — K.A. Applegate

We can't tell you who we are. Or where we live. It's too risky, and we've got to be careful. Really careful. So we don't trust anyone. Because they find us ... well we just won't let them find us.

The thing you should know is that everyone is in really big trouble. Yeah. Even you.

The Animorphs have met the Ellimist. He "helped" to save the kids when they were about to be eaten by a Taxxon. He "helped" to free two Hork-Bajir and restored Tobias's morphing ability. But, even though the Ellimist has enormous power, he is not all-powerful. He has an enemy. The Crayak.

So, the Crayak and the Ellimist decide that a battle will prove their ultimate power. But they don't intend to fight each other: The Ellimist will choose the Animorphs, Ax, and Erek, the Chee; the Crayak will choose his own army. If the Animorphs lose they will be erased from the universe altogether. And there'll be no one left to fight the Yeerks. . .