Escaping from Costa Rica on a murder rap, Captain Gringo hightails it to neighboring Honduras hired out as a munitions officer for a certain General Morales. His outfit, The Iron Brigade, is a gallows crew of murderous misfits. Their mission: to turn back the British troops invading the north. Meanwhile, Captain Gringo's got a little action of his own, a man-sized Amazon who gets her money smuggling guns and her kicks making love.