My name is Aximili-Esgarrouth-Isthill.

This might suggest to you that I am not a human. In fact, I am a member of the Andalite species. In my natural state, I do not resemble a human at all. I am a blue-furred quadruped with four eyes, a bladed tail, and no mouth.

It would be very nice to always have a mouth.

Nevertheless, I have been a human on many occasions. Biologically, I am equipped with the morphing power. It allows me to biologically transform into another species, at least for temporary durations. My human friends have allowed me to absorb their DNA, so that I might become a mixture of all of them.

Sometimes it is very pleasant to be a human. I enjoy the great sensation of human tastes. Humans have produced many wondrous foods. The glorious cinnamon bun! The unparalleled chocolate bar! The exquisite cigarette butt, whose like cannot be found in seven light years!

My human friends tell me that cigarette butts are not good for eating. I obey them, but it is difficult. Some of these human rules do not make very much sense.

While it is pleasant to use the morphing power to become a human, I much more frequently must use it for things that are not pleasant. This is because I am part of the resistance to the Yeerks on Earth.

The Yeerks are a species of parasites that come from yet another planet. They invade the brains of their hosts, or Controllers, and take them over. "Controllers" is a misnomer—they are the controlled. They cannot move, they cannot speak, they cannot communicate with the outside world in any way. It is the Yeerk that does everything.

They have conquered the dangerous if dimwitted Hork-Bajir. They have conquered the horrific Taxxons. They have conquered the Gedds of their pitiful home planet. But they have not yet conquered us Andalites. Only one Andalite has fallen victim to the Yeerk Empire. He is under the control of the Yeerk Visser Three. It was Visser Three who murdered my brother, Prince Elfangor.

They have not yet conquered the human race. It is my human friends and I who must stop them. They, too, have the morphing power. But it is not easy. There are only six of us in all, now, and they are all children. I, too, am only an aristh by my people's standards. I am a long way from home, though, and rank does not matter so much. My own rank, that is. I follow Jake, who is our Prince. He says he does not want to be, but he is.

The other "Animorphs", as they call themselves, include Marco, Jake's friend. He is an expert at human humor, a special dialect found in many human languages and even among Andalites. It is rather like simple folktales, which use untrue statements to convey high-level messages. I think.

Jake's cousin (the child of someone who is the sibling of one of your parents), Rachel, is also an Animorph, as is her friend Cassie. Sometimes Marco calls Cassie a "tree-hugger", although humans do not hug trees. Nor do they have Garibah. Sometimes, however, Cassie comes into close contact with other animal species. Actually, all of us do; it is only through physical touch that we can acquire the DNA of other species. Once this is accomplished, we can morph into these animals, temporarily becoming them. This power had only been available to Andalites, but my brother gave it to these humans as well.

Stay in morph too long, however, and you are trapped in the body of the animal you morph. This is what happened to my shorm, my best friend, Tobias. He was born a human, but now is a red-tailed hawk, a type of Earth bird. Through the intervention of an Ellimist, he is allowed to morph like the rest of us, but must always return to his hawk body after two hours.

We are the only ones who can fight the Yeerks.

While it is difficult to tell who among humans is a Yeerk, we have identified some of their schemes and destroyed many. Some remain in place, like The Sharing. While it calls itself an organization for humans to interact, it is really a means of identifying possible host bodies. Some weak-minded humans voluntarily permit Yeerks to inhabit their brains.

But besides The Sharing, many Yeerk ventures have been stymied. No matter how hard they try to blend into normal human society, the Yeerks make mistakes.

So do we.

This is the story of when we went wrong.