Based on the real life story of legendary cryptanalyst Alan Turing, the film portrays the nail-biting race against time by Turing and his brilliant team of code-breakers at Britain's top-secret Government Code and Cypher School at Bletchley Park, during the darkest days of World War II.

After India Stoker's father dies, her Uncle Charlie, who she never knew existed, comes to live with her and her unstable mother. She comes to suspect this mysterious, charming man has ulterior motives and becomes increasingly infatuated with him.