Teenage math prodigy Nathan (Asa Butterfield) struggles when it comes to building relationships with other people, not least with his mother, Julie (Sally Hawkins). In a world difficult to comprehend, he finds comfort in numbers. And when Nathan is taken under the wing of an unconventional and anarchic teacher, Mr. Humphreys (Rafe Spall), the pair forge an unusual friendship. Eventually, Nathan's talents win him a place on the UK National team...