In 2016, the pharmaceutical company Merck won a $200 million jury verdict against its competitor Gilead, based on Merck’s claim that Gilead infringed Merck’s drug patents. But three months later the judge completely barred Merck from enforcing its patents against Gilead, after concluding that Merck had “unclean hands” as a result of a “pervasive pattern of misconduct” that included “lying,” unethical business conduct,” and “litigation misconduct.” The $200 million verdict vanished in a puff of smoke. That result was affirmed by a federal circuit court of appeals in April 2018, and in January 2019 the United States Supreme Court declined to review the circuit court’s decision, leaving Merck out in the cold with its unclean hands and without its money. What are unclean hands? And how can they cost $200 million?