Conquered Earth novels

Earth has been conquered by an alien race known as the Assembly. The adult human population is gone, having succumbed to the Tone - a powerful, telekinetic super-signal that has reduced them to a state of complete subservience. But the Tone has one critical flaw: it only affects those over the age of twenty, which means that there is one group left to fight: teens. Two teens and a young girl with amazing powers must now stop the aliens' mysterious...