Following the death of her brilliant mathematician father, Catherine struggles to come to terms with his legacy. Inheriting some of both his brilliance and his instability, she is torn between her sister, Claire, who wants to take her back to New York, and Hal, a former student of her father's, who tests both her knowledge and her emotions. In Proof, David Auburn has fashioned a subtle and gripping exploration of loss, guilt, discovery, instability, and, ultimately, the elusive nature of truth.