Traveling from Wickenburg on his way to California, the stagecoach is waylaid by Indians and Sam is woulnded. Dragged to safety by one of the passengers, they witness another of the passengers, Georges Latrelle, shooting, killing and scalping the driver, messenger and other passengers, to make it look like they were held up by Indians. Sam is too hurt to give testimony and his fellow passenger, Ben Shaw, is in a hurry to get to California, himself. While in Ehrenburg on the Colorado River, Sam is invited to sail on a steamship, the Fortunado, along the coast and around the cape of Baja California. The poker games entice, and the owner of the ship, Alejandro Mateos, intent on making a go of his shipping business, needs his help against pirates. Elizabeth Fourchette, accomplice of Georges, is being squeezed out by Alejandro's sister, Adelita, and she uses poisoned wine to try to get her way. Seeing that he survived the stagecoach robbery, Sam isn't too keen on tracking down the mastermind, Georges Latrelle. However, their paths keep crossing and when Georges tosses him overboard into the Sea of Cortez, that is the last straw. Sam must see this through to the end, even if it takes a Poker Contest in San Francisco to do it.