Gantz: O

After being brutally murdered in a subway station, Kei Kurono (Yuki Kaji) awakens to find himself resurrected by a strange computer named Gantz, and forced to fight a large force of invading aliens in Osaka. In this bizarre game, he joins a team of others, including Reika (Saori Hayami) and Masaru Kato (Daisuke Ono), to kill every monster in the city within two hours, with the promise of points, bonuses, and freedom. As they navigate the gruesome battles, alliances are formed and broken, and the true nature of the game and its rules slowly come to light.