Antonio is an Italian-American chef who has been running his five-star Santa Barbara restaurant Antonio's for 10 years. When food critic Vince Wagner dies after eating poisoned risotto at his restaurant, Shawn and Gus go to investigate. Antonio tells them that he is glad Wagner is dead, as he never once received a good review from him. Just at that moment Lassiter and Juliet enter the kitchen to arrest him based on their own research. However, Chief Vick orders his release a while later when a homeless man dies after eating the remains of the risotto out of the trash while Antonio was in custody.
Shawn and Gus dig a little deeper and find out that Antonio was embroiled in a conflict with the vegetarian community some time earlier. They had complained about the poor taste of his veggie burgers, which he then responded too by secretly adding beef broth to the recipe. When this was discovered, however, tensions rose to such a height that the community's leader, Dwyer, started organizing boycotts while advocating to take Antonio down by any means possible. Shawn and Gus now believe that Dwyer might have murdered Wagner just so that she could frame Antonio for it and put him out of business once and for all. This turns out not to be the case, though, and the motivations of the real culprit, Nick, had nothing to do with Antonio personally at all. He simply considered Antonio the perfect fall guy because he had written Wagner an Angry Chef Letter (as Wagner's assistant Cooper calls them) containing a death threat after receiving another bad review.