After Donna, the account manager at Strickland Propane, is fired for stealing office supplies, Hank tells Peggy to apply for the opening at Strickland. To please Hank, Peggy unenthusiastically accepts the job, but secretly pursues a full-time job teaching Spanish at a Catholic school. Peggy gets hired (by pretending she's a nun) and loves her new job until she has to B.S. her way through an assignment as a substitute religion teacher. Peggy realizes that if she teaches her students untruths about religion, they might go to hell even though they didn't realize they were doing anything wrong. She even has a nightmare that she and the kids go to hell.
Hank informs Peggy of a teaching opening at a public school and urges her to apply. Upset, she confesses her ruse to Hank, who tells her to quit. Peggy says that if she confesses, her teaching career will be shattered. With the guidance of Bill, a lapsed Catholic, Peggy pulls an all-nighter to learn about Catholicism. Peggy teaches the correct tenets of the religion and then quits her job, saying she has fallen in love with a propane salesman. As penance, Peggy doesn't interview for the job at the public school.