The Substitute (Glee)
Cheerleading coach Sue Sylvester (Jane Lynch) is given the job of being the principal of William McKinley High School. She was given the job after causing Principal Figgins (Iqbal Theba) to be infected with the flu. Glee club director Will Schuester (Matthew Morrison) also gets the flu. He takes time off from work to get better. He is cared for by his ex-wife Terri (Jessalyn Gilsig). This leads to them sleeping together.