Difference is something to be celebrated, parents earnestly tell kids who don't fit in, trying to armor their children against the worst the world has to offer. When Nathan (Asa Butterfield) is diagnosed with autism, he's young enough to believe it when his dad tells him he has a superpower—that his faculty with numbers and patterns makes him special.
Which it does, of course, and he is—but by the time Nathan reaches adolescence, long after the death of his beloved father, he's also isolated, unhappy, borderline abusive to his mother (the wonderful Sally Hawkins), and singlemindedly fixated on earning a spot on the British team to compete in the International Mathematical Olympiad. When he wins a chance to train for the team, he leaves home and for the first time begins to grapple with his social limitations.
It's rare enough to see a movie about a kid with mental health issues who isn't a school shooter, but A Brilliant Young Mind is insightful and non-condescending as it portrays the coming-of-age challenges of a boy whose emotional wiring makes dealing with humans extra challenging.