River of Passion — Paula Fairman

Crystal Lee grew up on the mighty and mysterious Missouri under the stern guidance of her father, Marsh Lee, captain of the Missouri Mist riverboat. But none of the secrets of the great wide river are as well kept as the captain's. And no one is more stunned than Crystal and the man she loves when Captain Marsh reveals she is not his daughter and he wants her to marry the man she has always thought to be her brother...