The Case of the Three Rings is the 64th book in the Hank the Cowdog series by John R. Erickson. In this part, Hank becomes a victim in the plot to kill Hank. First the turkey was poisoned, then the poisoning caused Hank to fall to death. Famous events affect his reputation. All of these are aimed at the Hank dog. Hank thinks there is a mastermind who really wants to harm Hank through those schemes.