Mr. Schuester starts an investigation when a salacious list about members of the glee club circulates the halls of McKinley High. Meanwhile, Sue is mortified when a video of her performing the Olivia Newton-John classic "Physical" surfaces

The glee club works on a duet assignment, and Finn and Rachel plan to throw the competition so that Sam can have a shot at winning. Meanwhile, a love triangle between Mike, Tina and Artie develops.

Love is in the air at McKinley High when the glee club sets up a kissing booth for Valentine's Day. Things don't go as planned, however, and hearts end up getting broken.