You die, wake up in a room with a black sphere, and realize your second chance comes with a price that keeps getting worse. Gantz doesn't let you pretend survival has meaning, every mission forces you to choose between saving strangers and saving yourself, and the game doesn't care which choice you make. The shock isn't the gore or the aliens; it's watching decent people discover they're not decent enough to survive, then getting thrown back into the ring anyway. This show asks what you're actually willing to do when nobody's watching and death stops being the ending.

Kei Kurono makes an unusual choice for him: he jumps onto train tracks to rescue a homeless man and is killed. He comes to in a room with other people who have just died and a large, mysterious black ball. The ball opens to reveal weapons and odd black suits, orders the group to hunt an alien, and sends them to an unfamiliar place. With almost nothing to go on, Kei joins his childhood friend Masaru Katou and a woman he does not know. The three soon learn they are caught in a deadly game against green aliens and robotic monsters, one that tests Kei's skill, morals and will to live. Mixing horror, psychological drama and science fiction, the series is graphic and harsh, showing gore, sexual violence and the greed and ugliness of ordinary society.