Akari Hizamaru will do anything for his beloved childhood friend, including participating in an underground cage fight against a wild bear! As ridiculous as it sounds, Akari does not have any other choice. His friend is dying of a mysterious virus, and the fight is the only way he can get the money to pay for the procedure she so desperately needs. At first glance, it seems like Akari has no chance of beating the dangerous animal, but the brawl reveals that he might have some strange abilities of his own. Unfortunately, he discovers he has been betrayed and his dear friend may be beyond help. In the aftermath, he meets two people who are part of an organization intending to send a manned mission to Mars. Prior expeditions to Mars ended in disaster when the explorers encountered hostile, mutant cockroaches. Now, they plan another mission with the sole purpose of exterminating the giant monsters because they may be connected to the mysterious virus that is plaguing mankind. Why are there giant cockroaches on Mars? And why does Akari have mysterious abilities that make him well-suited to fight these mutants?