Set in the Vietnam war, the story follows the exploits of Commander Gabe Louvier from graduation in America to taking command of an Alpha assault support boat as part of the U.S. Mobile Riverine Force operating in the Mekong Delta. His first boat is shot out from under him. He locks horns with a fellow Alpha boat commander called Clarke who looks down on him because he's a Southerner. He befriends a South Vietnamese serviceman called Van Dinh who helps save his life. Then they all get involved in a battle with a captured Alpha boat the Viet Cong have been using to shoot up friendly villages as a means of blaming the Americans and turning the locals against them.