Peter decides to grow a moustache, but then he's mistaken for a fireman, so he lends a hand when a fire breaks out at a local fast food restaurant. The owner gives him unlimited burgers as a "thank you" but he eats so many that he eventually has a stroke. When Peter recovers, he vows to expose the fast-food company and becomes friends with a genetically engineered cow he meets after infiltrating the McBurgertown warehouse.

Peter and Lois's marriage is on the rocks, but when Brian wins the New England Rising Writer's award, the three of them head to Martha's Vineyard for a relaxing vacation. As Peter's drinking spirals out of control, so does Brian's self restraint as he professes his undying love for Lois. Peter and Brian test their friendship over the woman of their dreams.