On that ordinary evening, college student Kei Kurono unexpectedly reunited with his junior high school friend Masaru Kato at the tram stop.Their reunion should have been joyful, but due to an unexpected disaster, it became thrilling.When they rushed to the tram desperately to save a man who fell on the rails, they did not expect that this moment of heroism would change their fate.

The violent impact of the tram caused them to lose consciousness instantly.However, when they woke up, they found themselves in a closed room.There were seven other men in the room, as well as a large black sphere.This mysterious black sphere became the key to their next actions.

According to Black Ball's instructions, they need to put on combat uniforms and pick up weapons to assassinate an alien creature called “Onions”.If you successfully knock out “Starman” and survive to return to this room, GANTZ will give everyone a score.Those who accumulate 100 points will have the opportunity to be resurrected and return to their original world.

In order to win bonuses and survive, this group of people started a cruel killing game.However, in this game, some people kill for the prize, and some become ruthless in order to survive.Xuano Kei became more and more powerful at the critical moment of life and death, but Kato Masaru became more and more disgusted with this world dominated by violence, and he resolutely rejected this way of fighting.

In the days that followed, the relationship between Kurono Kei and Kato Masaru also underwent subtle changes.They were once best friends, but now they're on different sides.Kyono Kei fights hard for survival and victory, while Kato Masaru sticks to his beliefs and refuses to be assimilated by this world.

However, no matter how they choose, the world is full of endless challenges and dangers.They must face those cruel “Onions”, and at the same time deal with the betrayal and conspiracy of other contestants.Every day is a battle between life and death, and they gradually realize that the world is much more complicated than they imagined.

In the game of killing and survival, both Kei Xuanye and Masaru Kato experienced profound inner struggles.They began to question their choices and re-examine the world.In this seemingly ruthless game, they rediscovered the humanity they had lost and discovered the strength deep within themselves.

In the end, when they faced the final challenge, Kei Xuanye and Kato Masaru made different choices.In order to protect Kato Sheng and others, Xuano Ke bravely challenged the powerful enemy.In order to stop this senseless killing, Kato Masaru decided to sacrifice himself in exchange for the safety of others.