Animorphs

Ax and the Animorphs must destroy the Yeerk pool to take back Earth, but they may end up killing humans in the process.

The Animorphs, a group of young people who have been given the power to change into animal form in order to help fight the evil alien Yeerks, find themselves in trouble when Yeerk leader Visser Three discovers a way to cause a person to demorph.

Ax becomes infected with a disease which all of the Animorphs except Cassie catch.

Tobias and the other Animorphs investigate a woman who claims to be Tobias' long-lost cousin.

The blue box Elfangor used to create the Animorphs has been found by David, but David doesn't know what it is. The Animorphs have to get that box at any cost. David ends up on the run with the Animorphs and Ax, and may become the sixth Animorph.

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.

Rachel, 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, worries that her secret power will be revealed when she loses control of her morphing abilities.

The Helmacrons want revenge on Cassie because they believe that she stole their ship.

The Animorphs ally with the Ellimist against the Crayak.