As high school memories fade, Marc Pease (Jason Schwartzman) is left grappling with the shame of abandoning his role as the Tin Man in a production of The Wiz. Haunted by the moment he fled the stage while his mentor, Mr. Jon Gribble (Ben Stiller), offered him supportive words drowned by his anxiety, Marc's journey takes an unexpected turn eight years later. He becomes entwined with Meg Brickman (Anna Kendrick), a talented but disillusioned high school senior stuck in the chorus of Gribble's latest installment of The Wiz.
Marc's passion for his a cappella group, Meridian 8, is evident as he strives to breathe new life into their waning prospects with hopes of recording a demo tape. Yet, Gribble's stubbornness in refusing Marc's entreaties for collaboration stems from past grievances over Marc's hasty exit all those years ago.
While tidying up Meg's bedroom, Marc's intrigue leads him to uncover a cassette labeled "Meg singing." Instead of the usual vocal exercises, he stumbles upon an unexpected duet featuring Gribble, their harmonious exchange building into a moment overflowing with significance. Meanwhile, Meg wrestles with feelings of doubt regarding Gribble's intentions, pondering whether his compliments are genuine or simply an extension of her consistent placement in the background.
In a bid to preserve Meridian 8, Marc concocts a false meeting with Gribble, asserting that the director has given the group the go-ahead for their demo. This charade ultimately unravels, leaving him vulnerable and in tears on stage. On opening night of The Wiz, Marc finds himself reduced to chauffeur duty for an oblivious prom couple, enduring the final trimming of his long-derided ponytail.
Arriving at the theater during intermission, Marc makes one last appeal to Gribble about the demo, only to receive another cold shoulder. A bandmate's disheartening message that another member has left the group further deepens his frustration. Just as the poignant strains of the Tin Man's song drift through the auditorium, Marc storms in alongside Gribble, commandeering an empty classroom and confronting his mentor. With tension crackling in the air, Marc accuses Gribble of deliberately sidelining Meg as revenge against him, leading to a climactic moment where he destroys the tape that holds Meg's aspirations captive.
Taking bold strides fueled by newfound determination, Marc breaks off his relationship with Meg, citing their age difference as a barrier. This emotional upheaval coincides with catastrophic news: the actor portraying the Wiz has sustained an injury, putting the show in peril. Without hesitating, Marc seizes this moment, steps into the Wiz's role, and delivers a performance that electrifies the audience. Meanwhile, Meg, initially shattered by their breakup, rediscovers her passion for singing and gravitates back to the stage.
As this dramatic chapter closes, Marc confronts his past fears and emerges as a more self-assured performer. Fast forward a year, and he has reinvented himself as "The Marc Pease Experience," a professional singer radiating confidence and commanding the attention of every audience member.
