x+y demonstrates that a documentarian’s skills don’t always translate into the world of fiction films. Director Morgan Matthews has been making documentaries since 2002, but this film is his first foray into fictional features. x+y takes inspiration from his 2007 film, Beautiful Young Minds, telling the story of Nathan, an autistic, talented teenage mathematician (Asa Butterfield), his overwhelmed mother (Sally Hawkins) and his teacher (Rafe Spall). Like the documentary that inspired it, x+y focuses on Nathan’s efforts to compete in the prestigious International Mathematical Olympiad.

The film is well-intentioned, well-shot and well-acted, but nonetheless disappointing. Outside of a brief, harrowing scene involving self-harm, it eschews any nuanced investigation of its character’s interiority for blunt dialogue that repeatedly spells out the screenplay’s themes and objectives. We know Nathan struggles to fit in because we’re told as much over and over again. We know that his teacher is a failure, a ‘waste of potential’ because he’s referred to as such in every second line. It comes across like a bad documentary – a series of talking heads explaining their feelings and motivations – rather than a thoughtful piece of fiction, especially given its conclusion, which sidesteps one saccharine cliché only to immediately embrace another.