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 Earth and another planet are at stake.

"If you are chosen by the bizarre black sphere known as the Gantz, you are already dead. You remember dying, yet you can eat, sleep, have sex; it feels a lot like life. Strangers join you in this limbo. While some are good, some are very bad. All are dead like you--for now. You might be able to reclaim your mortality. But first, the Gantz demands that you undertaike missions of brutality and madness, killing aliens hidden among the population. It...

A small group of aliens from a dying race live as human teenagers in Roswell, New Mexico.