Mathematical genius Dr. Meg Brightwood has just completed her life's work, a proof of a problem so impenetrable it's nicknamed the Impossible Theorem.
Reclusive and burdened by anxiety, Meg hadn't been taken seriously before. Now everyone wants to get their hands on what she alone possesses, especially her own mathematician father.
Having grown up a prodigy in a field plagued by sexism and plagiarism, Meg opts for a public presentation so there will be no doubt of her authorship. But a panic attack obliterates her plans. In defeat, Meg returns to the decaying house where she lives alone and locks away the one and only manuscript of her proof.
Then chance sends her the unlikeliest of allies: Isaac Wells-carpenter, high school dropout, in trouble with the law. And the one love of Meg's life. Fifteen years ago, they never did more than hold hands. Now adults, they reach toward each other through the minefield of the past and find a tenuous space where they can love and be loved for who they are now.
But when Meg goes to retrieve the Impossible Theorem, she finds it missing. Will she fight for the achievement of the century and the love of a lifetime?
