Following a fine tradition of absorbing first-person narrative into third-person drama, the playwright Simon Stephens makes Mark Haddon's brilliant cult novel an ensemble piece about putting on a play.
In this case, it's 15-year-old autistic genius Christopher Boone's book that has been read by a teacher and turned into a schoolroom drama; but with amazing lighting that illustrates the algebraic conundrums at the heart of his emotional crisis.
A doggy corpse stuck with a garden fork sets Christopher (Luke Treadaway) off on his detection trail. Who killed the dog? And: where's my mother?
This is a profoundly moving play about adolescence, fractured families and mathematics, with a superb support cast of Niamh Cusack, Paul Ritter and Nicola Walker. But it is the remarkable Treadaway's evening: he nails the required tone of headlong intellectual assurance and unguarded neediness.
(020 7452 3000; nationaltheatre.org.uk) to 26 Oct