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"Still, these wolf bodies are not equipped for the Arctic or Antarctic or wherever we are. We might be able to survive for a few hours at a time, long enough to remorph and regenerate, but we're still vulnerable. Too vulnerable to be fighting."

The Extreme, published in December 1998 and written by Jeffrey Zeuhlke based on an outline by K.A. Applegate and Michael Grant, is the twenty-fifth book in the Animorphs series. It is the seventh book narrated by Marco and his fifth book as sole narrator.


Official Description

Marco, the other Animorphs, and Ax have managed to find out where the Yeerks are planning to build their next ground-based Kandrona. That's a good thing. The location is supposed to be somewhere near the North Pole. That's a bad thing. The Animorphs and Ax know that the Yeerks are a "cold-blooded" species, but this is a little nuts! Who wants to be near the North Pole without Arctic morphs -- and wearing spandex?

Even so, the kids know that if the Yeerks succeed with their plan, Earth is pretty much done for. And Marco, the other Animorphs, and Ax aren't quite ready to give up the fight...

Plot Summary

This section needs a rewrite

Erek King tells Marco about the Yeerks' plan to manipulate U.S. satellites to beam Kandrona rays into swimming pools, turning each into a Yeerk pool. That way, Controllers won't have to travel to the Yeerk pool, and the Animorphs would lose their advantage over them. The Yeerks are conducting their latest scheme in the Arctic Circle.

The Animorphs hitch a ride on Visser Three's Blade Ship as flies. On board, they discover cryogenic tubes with strange creatures inside them. Their presence is discovered by the Yeerks, and they're forced to morph their battle creatures. Jake orders a distraction, and Marco rips open the control panel to open the ship's hatch. Rachel, with all her grizzly bear might, manages to make a single, tiny crack in one of the specimen tubes. A liquid nitrogen-like mist spills out, freezing every living thing it touches. A nasty fight ensues, and the Animorphs bail out.

Falling out into the frozen tundra, the Animorphs find themselves freezing to death. They morph wolves, but they need energy to keep going. At night, since none of them can sleep, Ax informs them about the new aliens, the Venber, that was wiped out centuries ago by a race known as "The Five", melting them for computer semiconductors. Not only that, but the Yeerks have cloned them by cross-breeding them with humans, giving them their new humanoid shape. Then, they find a polar bear that had just killed and partially consumed a ringed seal. The Animorphs eat the remains. Much to their surprise, not even Cassie has any scruples. They also find two seal pups – the pups of the seal they'd just eaten. Regretfully, they acquire the pups and leave them to their fate.

Soon the Animorphs find themselves pursued by the creatures Marco had observed in the tubes. They morph seals to escape them, but are attacked by orcas in the freezing depths.

Later, they come across Derek, a young, jocular Inuit, and his "buddy", Nanook the polar bear. Derek tells them about the people with the satellite dish, and how they're even worse than the people from New York and Detroit who come to the Arctic to shoot wildlife from helicopters for sheer pleasure. The Animorphs are presented with an opportunity to acquire the DNA of a native animal, and so they attack Nanook, minimally injuring him. After Marco (as a gorilla) and Rachel (as a grizzly bear) pin him into submission, they each acquire and morph him.

The Extreme illustration

The six Animorphs in polar bear morph

The Animorphs, in their new polar bear morphs, advance on the Yeerk base. They encounter the Venber, engaging them in a brutal battle. They lure the remaining Venber into the hangars, where the above-zero conditions cause them to melt. The Animorphs then steal a Yeerk Bug fighter, and Marco immolates the Yeerk base, although not before waiting for human-Controllers to evacuate the buildings before destroying the structures. When the base is decimated, Ax immediately flies south. Soon to be intercepted by the Blade ship, they morph birds and destroy the Bug fighter, spending the next two days alternating between flying and hitching rides on trucks and trains before they return home. Once home, Marco relishes the feeling of a hot shower, and his dad laments that Marco's room is no longer tidy as it was the past few days.



Supporting Characters:


Other Characters:



Major/Highlighted Events

  • The Animorphs travel to the North Pole, destroying the Yeerks' Arctic base where they plan to house their new ground-based Kandrona, capable of transforming any body of water into a Yeerk pool.
  • This marks the first occasion where the Chee pose as the Animorphs while the Animorphs are on an extended mission.
  • Marco discloses that Rachel and Tobias's relationship extending beyond that of a friend and an Animorph is not a secret to the others, shocking Rachel when Marco refers to her as Tobias's honey.
    • Rachel also keeps Tobias, who does not have a cold-weather morph, on her chest, with her in grizzly bear morph and Tobias in flea morph. When Jake asks her to morph into the wolf and pass Tobias to him as she demorphs, Rachel states that Tobias can stay on her chest as she passes from bear to human to wolf, with Tobias adding that it wouldn't matter that he is on Rachel's human chest since he is in flea morph and thus cannot see anything anyway.


Morpher Morphs acquired Morphs used
Jake Baby Ringed Seal, Polar Bear (Nanook) Peregrine Falcon, Housefly, Siberian Tiger, Wolf, Baby Ringed Seal, Polar Bear (Nanook)
Rachel Baby Ringed Seal, Polar Bear (Nanook) Bald Eagle, HouseflyGrizzly Bear, Wolf, Baby Ringed Seal, Polar Bear (Nanook)
Tobias Baby Ringed Seal, Polar Bear (Nanook) Housefly, Flea, Baby Ringed Seal, Polar Bear (Nanook)
Cassie Baby Ringed Seal, Polar Bear (Nanook) Osprey, HouseflyWolf, Bottlenose Dolphin (Monica), Baby Ringed Seal, Polar Bear (Nanook)
Marco Baby Ringed Seal, Polar Bear (Nanook) Osprey, HouseflySilverback Gorilla (Big Jim), WolfBottlenose Dolphin, Baby Ringed Seal, Polar Bear (Nanook)
Ax Baby Ringed Seal, Polar Bear (Nanook) Human (Main), Northern HarrierHousefly, Flea, Baby Ringed Seal, Polar Bear (Nanook)


  • The cover quote is, "So many Yeerks, so little time...."
  • The inside cover quote is "Can you say 'cold'?"
  • This is the first book in the series to be ghostwritten.
  • This is the fourth instance where the Animorphs are on a mission on Earth outside of their hometown, and the second time where they leave North America.
  • This is the fifth book in which all the Animorphs acquire the same new morph.
  • Marco mentions having being sent back 65,000,000 years into the past, referencing the events of In the Time of Dinosaurs.
  • ANIBASE: A lot of things influence a writer. For Katherine Applegate, this time it was the weather. This book was created during a particularly cold time of the year in her former hometown of Minneapolis when it was below freezing outside!


  • "Visser Three's" is written as "Visser's Three" on p17.
  • Jake has Tobias and Ax on him on p92, but Marco has them on p98, without there having been an opportunity for the fleas to switch.
  • Jake struggles to survive in the North Pole when in tiger morph. However, Jake's morph is specifically a Siberian tiger, which is adept at surviving in cold weather environments.
  • Ax says that the Venber are not carbon-based, but also states that they have DNA, which is carbon-based.
  • Jake asks what weapon the Venber are firing at them, and Ax replies that they are using Dracon assault cannons, although Ax was a flea at the time and thus would have felt only vibrations, and would not have been able to know exactly what specific weapons were being fired.
  • Marco claims that he has been on a Bug fighter before and thus knows his way around the weapons system. However, the only time the Animorphs ever entered a Bug fighter in the past was in The Forgotten. While Marco did operate the weapons system, this timeline was erased, with only Jake retaining the memories of the events. Therefore, Marco has never been on a Bug fighter before and should not know how to operate the weapons.
  • Marco says the pair of Venber are still looking for them in the Arctic. However, in The Escape, Ax informed them that when a Yeerk base is destroyed, the mind-control chips that the Yeerks use liquefy. Therefore, upon the destruction of the Arctic satellite station, the two remaining Venber should have died.


U.S. Images

International Covers

Main Series #1 The Invasion | #2 The Visitor | #3 The Encounter | #4 The Message | #5 The Predator | #6 The Capture | #7 The Stranger | #8 The Alien | #9 The Secret | #10 The Android | #11 The Forgotten | #12 The Reaction | #13 The Change | #14 The Unknown | #15 The Escape | #16 The Warning | #17 The Underground | #18 The Decision | #19 The Departure | #20 The Discovery | #21 The Threat | #22 The Solution | #23 The Pretender | #24 The Suspicion | #25 The Extreme | #26 The Attack | #27 The Exposed | #28 The Experiment | #29 The Sickness | #30 The Reunion | #31 The Conspiracy | #32 The Separation | #33 The Illusion | #34 The Prophecy | #35 The Proposal | #36 The Mutation | #37 The Weakness | #38 The Arrival | #39 The Hidden | #40 The Other | #41 The Familiar | #42 The Journey | #43 The Test | #44 The Unexpected | #45 The Revelation | #46 The Deception | #47 The Resistance | #48 The Return | #49 The Diversion | #50 The Ultimate | #51 The Absolute | #52 The Sacrifice | #53 The Answer | #54 The Beginning
Megamorphs The Andalite's Gift | In the Time of Dinosaurs | Elfangor's Secret | Back to Before
Chronicles The Andalite Chronicles | The Hork-Bajir Chronicles | VISSER | The Ellimist Chronicles
Alternamorphs The First Journey | The Next Passage
TV Tie-Ins Meet the Stars of Animorphs
Graphic Novels #1 The Invasion | #2 The Visitor | #3 The Encounter | #4 The Message | #5 The Predator | #6 The Capture