Beer chemist Rory Harper loves his job and has the beer belly to prove it. He also has a problem. Named Arthur. With an endless barrage of fat jokes and obnoxious pranks, Arthur turns Telluric Lake Brew Works into Rory's personal hell. Revenge fantasies are all Rory has to soothe his battered ego and during a company party, he decides to carry out the "perfect," anonymous payback.
But something goes wrong. Arthur, who should be home afflicted with explosive diarrhea, shows up the next day unscathed, and Rory's seventy-year-old boss is dead in the taproom. The coroner rules it a heart attack, but Rory's not convinced. Some careful digging confirms Arthur switched the beers. But is the spiked beer what caused the boss's heart attack? Did Arthur know it was spiked?