Tim has to cast an entire festival of short plays. Penny, who has just returned to New York from Los Angeles, worries that she has become irrelevant. Penny serves as a reader for Tim during his auditions, where she re-connects with her long-time crush, Eric.

Linda asks Tim to cast a prestigious new play, Iron Dog, which will be running in Boston. Eric tells Penny about a new acting class he's taking, and Raina convinces Penny to attend. Tim and Steven, who recently broke up, unknowingly flirt with each other on a dating site. The acting class turns out to be ridiculous, and Penny and fellow student Aaron bond while making fun of it.

Penny participates in a reading for the musical Intersections, whose cast is led by Eric. While Penny is away, Tim calls Aaron as a substitute reader for Iron Dog. During the Intersections rehearsals, Penny is annoyed by the flirting between Eric and the female lead. The Intersections reading is disappointing.

Aaron helps Penny with her own planned audition for Iron Dog, and confesses that he is applying to law schools. Penny auditions for a touring production of a Mean Girls musical. Eric comes in for the Iron Dog audition, and Aaron, annoyed at and jealous of Eric, delivers a bravura performance reading opposite him. Linda decides that she wants Aaron to audition for the play. Penny becomes taken with Aaron and the two go out on a date, but Aaron doesn't tell her about his good news in order to spare her feelings.

Tim keeps the news about Aaron a secret from Penny. At a party for potential investors for Iron Dog, Linda meets Steven and his new boyfriend Cameron, and Steven reveals to Linda that Tim is gay. Penny auditions for Iron Dog. Penny finds out that Aaron was asked to audition, and was cast, and the two have a fight. Penny gets cast in the Mean Girls musical.