Japanese action film in which two friends killed in an accident find themselves reborn as alien hunters. Teenagers Masaryu Kato (Kenichi Matsuyama) and Kei Kurono (Kazunari Ninomiya) are close friends. When a man falls onto the tracks at a subway station, the pair endeavour to save him, but lose their own lives in the process. The pair awake in a mysterious apartment dominated by a black orb known as 'Gantz'. Unsure whether they are alive, dead or in another dimension altogether, they find themselves charged by Gantz with the duty of heading out into the world to seek and destroy aliens. The stakes are high: pull off their missions successfully and they will keep what life they have for another day; fail and this time they won't wake up.