Many Japanese movies are based on popular manga and/or anime series (or maybe just the ones I watch?). Gantz is no exception – it is a manga written by Hiroya Oku, which has sold over 17 million copies. More recently, it has also been released as a 26 episode anime series.
The movie Gantz and its sequel titled Gantz 2: Perfect Answer were both released in 2011, stars Kazunari Ninomiya (member of the famous Japanese boy band Arashi) and Kenichi Matsuyama (starred in Death Note).
Childhood friends, Kei Kurono and Masaru Kato, who were just about to be hit by an oncoming subway train, find themselves in a strange apartment with a mysterious giant black sphere and others who have recently died. The massive black sphere in the center of the living room is Gantz, who assigns the people gathered in the room on missions to exterminate aliens. They are given a set time and if successful will receive points. A total of 100 points will allow them to leave this purgatory like place or send someone else back to life. If they fail, they can perish forever.