The play concerns Catherine, the daughter of Robert, a recently deceased mathematical genius and professor at the University of Chicago, and her struggle with mathematical genius and mental illness. Catherine had cared for her father through a lengthy mental illness. Upon Robert's death, his ex-graduate student Hal discovers a paradigm-shifting proof about prime numbers in Robert's office. The title refers both to that proof and to the play's central question: Can Catherine prove the proof's authorship? Along with proving the proof, the daughter also finds herself in a relationship with 28-year-old Hal. Throughout, the play explores Catherine's fear of following in her father's footsteps, both mathematically and mentally.