When they begin to gain weight, Jerry and Elaine suspect that Kramer has made a bad investment in a non-fat yogurt shop. Jerry inadvertently uses the "F" word, as a result so does Meredith's son Matthew, a lot. George meets an old childhood friend whom he is convinced is trying to humiliate him. Elaine begins dating this friend and gives him an idea for his mayoral candidate's campaign. Kramer's date with a lab technician results in strange test results for the future mayor of New York City.