Katie Gordon met Tom Nichols while playing in summer stock at the Red Bridge Playhouse in Connecticut. Twelve years later, Katie, by then a well-known actress, made her play for Tom. They began an intense affair that ends disastrously. A dozen years after their breakup and again desperately unhappy with her life, Katie encounters Tom a third time when he returns to Red Bridge to play a fund-raiser for the theater in which he and Katie had played summer stock. Now a successful musical playwright, Tom's songs for his hit Broadway musical become the score for Katie's re-awakening as she must confront her past and decide her future when she and Tom finally play their 'Third Act'.