It’s delightful to see the Unicorn launch its spring season headliner with such a visible spring in its step. It’s hit a bull’s-eye with Carl Miller’s charming adaptation of the 2007 children’s book by Siobhan Dowd. No wonder the sassy production has such a Tigger-esque bounce.

There are distinct echoes of Mark Haddon’s The Curious Incident of the Dog in the Night-Time in Dowd’s quirky boy detective Ted, whose Asperger’s syndrome — and obsession with meteorology and hatred of metaphors –— help him and sister Kat crack the mystery of their cousin Salim’s disappearance from a trip on the titular big wheel.

Miller and director Rosamunde Hutt sensibly elect to wear the themes of family discord and teenage rebellion lightly rather than to thump them home as “major issues”. It’s impossible not to warm to John Cockerill’s wide-eyed and tousle-haired Ted, who manages to be both at the heart of and at an angle to every situation in which he finds himself.

I’d strongly recommend that major casting departments head along to look at this most promising young actor.

There’s able support from Amaka Okafor, who imbues Kat with confident, muscular energy. It’s good, too, to see a family show that doesn’t outstay its welcome but buttons everything up in an efficient 90 minutes. No mystery: this is a cracker.

Until 18 April. Information: 020 7645 0560, www.unicorntheatre.com