You and The Breakfast Club find yourselves in the middle of an alien invasion by a slug species known as the Yeerks with their only weapon being the power to morph into any animal they touch provided by Elfangor who dies protecting them from the Yeerk leader, Visser Three. Controllers (humans and aliens with the Yeerk slug dictating their every move) are everywhere and you must keep this a secret from everyone around you. One wrong move and you risk death or worse... enslavement.

Andrew: The reluctant leader of the group. At first, he dismisses it as a dream until discovering that his own mother, in her attempt to become more independent from his father, joined The Sharing (a club used as a front to collect human bodies for the Yeerks to use as hosts) and unwillingly became a Controller with a Yeerk living inside her brain. He's vowed to save her at all costs. Andrew's battle morph is the tiger and his bird morph is the falcon.

Claire: The one who most refused to believe the Yeerks were there, wanting to go back to her normal life. She is the best at morphing, the only one who can make it look beautiful, and joined when she realized that the Yeerks were breaking up happy families because they could. However, she hates the war and how it's changed everyone around her. Claire's battle morph is the wolf and her bird morph is the osprey.

Bender: After watching Elfangor die, he was the one most determined to fight in the war. Bender has an insatiable bloodlust tempered only by his sarcastic remarks and is the only one who would cry if the war ended. Seeing a burnout friend begging and screaming to be free in the Yeerk Pool increased his determination. When there's a dangerous mission, he is the first to volunteer. He often collects the most powerful morphs he can find but his battle morph is the Grizzly Bear and his bird morph is the bald eagle

Allison: Also eager to join the battle, Allison spends most of her time in the form of a red-tailed hawk to escape the problems of her every day life. Unfortunately, she stayed in the morph longer than two hours and, as a result, must spend the rest of her life as a hawk. Seeing that the Yeerks prayed on lost souls like her to turn into voluntary controllers convinced her to join the fight. Allison spends most of her time scouting out possible Yeerk locations and keeping watch for safe spots to morph and demorph in an attempt to not be useless despite not being able to morph.

Brian: At first, he was afraid to join the battle because of what it would do to his academic performance. Then realizes that, if the Yeerks take over Earth, there will be no college but what really seals the deal is the fear that his sister will be infested. Brian brings his knowledge of different animals to the group, helping them know what to expect so they can better control the instincts of the animals. His battle morph is the gorilla and his bird morph is the osprey.

Jasmine: She is one of the first to agree that they have to stop the Yeerks partly due to feeling in debt to Elfangor and partly because of her fear of being silenced like her mother. Jasmine is quite capable of planning, something she uses to make sure everyone gets out alive. She also acts as the moral support, trying to keep everyone believing no matter how hopeless it gets. Her farm is the base of operations for the group and is friends with the farm's on-call vet who also works at the zoo, giving the group connections to all sorts of animals they can collect DNA from. Controller Vernon's attempt to recruit her for The Sharing by playing on her grandfather's concern is the final motivation for her to fight. Jasmine's battle morph is the spotted hyena and her bird morph is the northern goshawk.

Scenarios

#1. Elfangor dies trying to protect The Club from Visser Three and now The Club has to learn how to use their morphing powers and discover how the Yeerks operate.

#2. The Club wants to attack the Yeerks again, but they need more information.  So it's up to Jasmine to infiltrate the home of Visser Three's most trusted lieutenant, Richard Vernon.

#3. When Allison discovers that the Yeerks have a cloaked truck ship collecting air and water from Earth for their ship, she gets the Club to help her decloak it and expose the Yeerks once and for all.

#4. The Club is having strange dreams about a voice calling for help and end to the ocean to rescue whoever the voice belongs to.

#5. Ax helps the Club set up a trap for the Yeerks where they discover the true leader of the Yeerk Invasion, Visser One, whose host is someone important to a member of the Club.

#6. While trying to stop the Yeerks from infiltrating the White House, Andrew becomes a Controller.  Now the Club has to starve that Yeerk out and make sure it doesn't escape to Visser Three.

#7. The Ellimist introduces himself to the Club and gives them a choice, leave Earth and save only a few humans or stay and lose to the Yeerks.

#7.5. Determine to uncover the "Andalite Bandits," Visser Three sends his Veelek to capture them one by one.  Meanwhile, Brian loses his memory and finds himself in the middle of nowhere.

#8. The Club educates Ax on the ways of humans, trying to help him blend in.  Then discover that Ax has been keeping secrets from them, making them wonder if they can even trust him.

#9. Desperate to find the "Andalite Bandits," the Yeerks create a phony logging camp in order to chop through the woods, knowing that Andalites can't survive without grass.  It's up to the Club to stop this and protect, not only Ax, but their own identities.

#10. The Club meets Erek King and a race of android allies called the Chee, wanting to help them fight the Yeerks.  Unfortunately, the Chee are pacifists and only the Club can help them find the very piece of technology to deprogram it.

#11. The Club discovers a crash landed Bug Fighter that they hope to use to reveal the Yeerk Invasion to Earth.  Unfortunately, bad piloting leads them to crash into the Amazon Rainforest.

#12. Jasmine absorbs a crocodile, creating an allergic reaction that causes her to morph uncontrollably.  Meanwhile, a pre-teen idol is about to talk up the Sharing and the Club has to stop him while making sure Jasmine's uncontrollable morphing doesn't expose their secret.

#13. Allison finds free Hork-Bajir trying to escape the Yeerks.  If she succeeds, the Ellimist will give Allison her ability to morph back, maybe even make her human again.

#14. There's a secret base called Zone 91 that claims to have proof of alien life.  The Yeerks want to access it and the Club has to stop them.

#15. Visser One's back and running a secret underwater operation.  It's up to the Club to stop Visser One, but there's a certain member who might not be able to face this Yeerk leader.

#16. Technology's taken a huge leap and The Club just found a website devoted to exposing the Yeerk threat.  Is it the work of an unknown ally or a clever trap?

#17. The Club discovers that the Yeerks have a weakness, oatmeal, and it drives them crazy, literally.  Now they have to figure out how to use this weapon to their advantage.