On an island off the coast of Mexico, former soldier of fortune Burr Whitman lives alone, studying butterflies. He hopes he has left behind a violent past, but the mysterious disappearance of a friend, and a lucrative new mission combine to lure him back into a world of intrigue and bloodshed. Burr's mercenary company, Argonaut, is hired to recapture an emerald mine from rebels, deep in the Colombian Amazon. It should be a straightforward operation, but in the jungle shadows, nothing is as it seems: flowers look like bees, leaves turn out to be insects; bitter rivals become collaborators, friends become ruthless enemies and the forest itself is both adversary and ally. Burr must contend with shifting alliances, betrayal in his own camp and the distractions of the idealistic doctor Leila Walcott, searching the jungle for medicinal plants. And the region is in the grip of emerald fever, swept by rumours of the fabled lost city of El Verde. Marxist guerrillas, right-wing death squads and Indian tribes are locked in an increasingly bitter struggle for the forest's wealth. The carnage mounts until the very survival of the rainforest is at stake and Burr finds himself fighting desperately - for much more than a paycheck.