A gambler and a prtty hostess have been found dead on the banks of Lake Bowie. Although it looks like a murder-suicide, Walker senses that this crime is more complex. A trail of clues leads to an illegal gambling ship, the Lone Star Belle, and its owner, Jack Springer. Now Walker, Trivette, C.D., and a lovely deputy named Robin must take a daring undercover assignment - and put the ship and the murderers away for good. But another set of criminals is aboard the Belle - men determined to destroy them all, if Walker and his fellow Rangers can't stop them...