Thread: What exactly is Gantz about?

I've never heard of this at all, and I'm considering downloading some chapters. Could someone give me a quick overview? Thanks.

One day, an ordinary higschool student is in the subway. A drunk beggar from the streets jumps down on the tracks. An old acquaintance of his jumps down and tries to help the beggar. The situation is getting desperate but no one else has the balls to jump down and help him. The main character "Kei", hopes that his "friend" wont see him but he does and is forced to go help him to save face in front of the crowd. They manage to save the beggar but the subway starts reeling in. They decide to make a run for it because they think that the train will stop at the station. Its an express train. It doesnt stop and it kills them instantly. Decapitating and cutting up their bodies. Kei then finds himself inside a strange room with a giant black ball in the center.They both try desperately to open all the doors and try escaping but to no avail. Some other people are in the room too, all of which had just died. Suddenly, strange music emanates from the ball and a screen pops out and says to go kill an alien. They then get teleported to a location outside of the room. What is going on? What is the black ball? Why are they supposed to kill aliens?

This is basically what happens in the first chapter. It's very graphic and it also contains sex scenes. Personally i think there are a few plot holes but i'm sure any die hard gantz fan will deny that. Its a good read.