Twilight of the Animorphs

[AU] On their last day of Summer Camp a group of friends go for a hike and find a dying Andalite. They're offered the power to morph and warned of a new threat. They're not the first to invade Earth, but they're the first with the power to end it. They must learn fast, for discerning friend from foe is harder than they know, and one mistake is all it will take to kill them all