After Kei and his childhood friend, Kato, are torn into bloody pieces by a speeding train, they awake in an unfamiliar room, surrounded by strangers. In the middle of the room is a bizarre black sphere: the Gantz.

If you are chosen by the bizarre black sphere known as the Gantz, you are already dead—yet you might be able to reclaim your mortality. First, the Gantz demands that you undertake brutal missions of madness, killing aliens hidden among the population. It is your only chance and you have no choice. You must play this disturbing game. And if you die again—and you likely will—it’s permanent.

The scores are tallied and Nishi explains some of what he knows about the rules of the strange world of the Gantz. The unusual situation grows even odder the next day when Kei wakes—and finds that this nightmare is no dream.

Seemingly back among the living, Kato must protect his brother from their hateful aunt. Meanwhile, Kei’s special suit gives him an advantage against the bullies at school. But will it help him when Kishimoto appears at his door?

Despite his best efforts, Kei remains unsatisfied during Kishimoto’s overnight stay at his apartment. At the place Kato calls home, more ugly evidence of abuse piles up.

Kato’s patience is being tested. At home, the abuse dished out by his aunt pushes him to the breaking point. Meanwhile, at school, a group of bullies forces him to take decisive and drastic action.

A new round begins for the gang. Appearing before the Gantz, they find themselves joined by a diverse group of fresh players. As the game gets underway, Kei panics when he realizes his suit is nowhere to be found.

As the group prepares to track down the Suzuki alien, Tetsu’s gang is creating conflict and Nishi’s smart mouth isn’t helping the situation. When tensions boil over, blood is spilled before the hunt even begins.

Kato is forced to take action to save Nishi from certain death, but he may not be ruthless enough to kill the Suzuki alien. Time is running out for yet another player trapped in the cruel world of the Gantz.

The group is beginning to figure out the rules of the twisted game in which they are caught, but survival is still far from guaranteed as the battle with the remaining Suzuki aliens erupts.