When Mr. Schuester gets sick, a substitute teacher takes over his Spanish class and the glee club, and winds up winning over the whole New Directions clan. Meanwhile, when Sue fills in for Principal Figgins as McKinley's top dog, she tries to flex her power on campus.

New Directions heads to the big Sectionals competition to go head-to-head against the Warblers and the Hipsters. While trouble brews between some of the young couples, Emma and Carl grow closer.