Rachel, one of the Earth teenagers dedicated to stopping the parasitic alien race known as the Yeerks, is horrified when she finds herself split into two nearly identical girls.
The Yeerk that controls Jake's brother Tom is desperate to keep Tom from going with the family to his great grandfather's funeral, even if he has to kill Jake's father to do it.
When the Animorphs try to stop the tiny alien Helmacrons from taking the morphing cube, Marco gets in the way and ends up with Helmacrons up his nose and inside his head.
Jake and his friends are given the power to morph into animals by a dying alien who tells them the Earth is under attack by the invading Yeerks, and they are called upon to test their new abilities almost immediately when they learn that Vissar Three, deadliest of the Yeerks, is after them.
The Yeerk that controls Jake's brother Tom is desperate to keep Tom from going with the family to his great-grandfather's funeral, even if he has to kill Jake's father.
Jalil, David, Christopher, and April, trapped in the nightmarish Everworld, regret trading a chemistry book for a knife when the alien Coo-Hatch use its information to build deadly new weapons.
