In the book the two main characters are a boy and girl who have turned 18 against all odds being immune to a genetic virus or disease alien invaders released onto the earth that turns anyone older than 18 into mindless slaves who eventually loose all sanity and die. the girl knows how to construct "artifacts" out of everyday objects that have been brought back from another plane the aliens have brought to life. oh and there is a young girl who the 2 main characters save from the aliens who had been givin power from the aliens. oh and the aliens are energy beings who control walking machines that have 3 eyes.