From the introduction:
It's 1943. You're a marine stationed on the island of Onna Oa, a tiny locale in the Pacific theater. You and your fellow marines - about fifty in total - have been charged with keeping it out of the Japs' hands. It should've been a simple task; Onna Oa's not large enough to be useful as an airbase, not close enough to anything to be strategically significant. Apart from the bugs, it should've been a few months of light duty and sunshine in an island paradise.
Instead, none of you are coming home alive. Some crazed Japanese general or admiral - whatever it is they have - has decided to make Onna Oa his priority. Every day at the crack of dawn you're greeted with a fresh assault - foot soldiers supported by a few bombers in the air. Yeah, the Japs are sitting ducks wading ashore like that, but they're crazy, and they have numbers. It's a war of attrition that you're losing badly.