The Extreme (Animorphs #25‪)‬

Marco and the other Animorphs have managed to find out where the Yeerks are planning to build their next ground-basedKandrona. That's a good thing. But the location is supposed to be somewhere near the North Pole. That's a bad thing. TheAnimorphs know that the Yeerks are a "cold-blooded" species, but this is a little nuts! Who wants to be near the North Pole withoutArctic 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 and the otherAnimorphs aren't quite ready to give up the fight.