Fifteen year-old Daniel has followed in his parents' footsteps as the Alien Hunter, exterminating beings on The List of Alien Outlaws on Terra Firma, but when he faces his first of the top ten outlaws, the very existence of Earth and another planet are at stake.
Fourth-grader Zack McGee's life is turned upside-down when Amp, a tiny alien, crash-lands in his bedroom, then causes trouble at school while trying to get parts to repair his spaceship.
As Daniel X continues to hunt for intergalactic aliens, he and his friends go to England searching for Berta, an outlaw who takes the form of fire and who killed Daniels's parents when he was two years old.