eppei and Kamiya, two average joes working in the electronic services industry, stumble upon the intergalactic bounty-hunter Ilia, and her partner, the artificial intelligence named Bob. Both men are accidentally transported to the Zone, a virtual reality in which Bob has trapped Ilia's latest prey, a biological weapon named Zeram. The Earth natives must both survive the experience and help Ilia capture Zeram before the Zone disappears around them.

Overview from themoviedb.org