It is an era of chaos. Earth is no longer the same as it once was. It has been overrun by a bug-like species known as the Blue. Twenty years ago, Yuji Kaido, who suffers from a mysterious illness, was placed in suspended animation in hopes of finding a cure. Upon waking, Yuji discovers that more than two decades have passed since his cryogenic sleep, and the world is now dominated by these creatures. He subsequently decides to join a unit of soldiers battling the Blue, driven by the hope of a better future.