Part of the beauty of Giles Andreae and Russell Ayto's Captain Flinn and the Pirate Dinosaurs series of books for young children is the way it throws together fantastical elements with gleeful, unrestrained abandon.

Secret doors in broom cupboards tumble out onto pirate ships on the high seas, and islands are filled with marauding, stylised dinosaur brigands. Without a huge budget this would be a difficult theatrical transfer, but Les Petits has executed this sequel to their original adaptation with lively invention.

Consciously aping the style of a school play, writer Oliver Lansley's version tells of Flinn's quest to rescue his friends Pearl and Tom from the clutches of Captain T-Rex and his crew.

At times the atmosphere builds almost too well, with the abduction of the children in rumbling darkness creating a spike of tension which is a little overpowering for smaller audience members. Yet the swashbuckling characters are brave and plucky, even when faced with perils like the dinosaurs' mincing machine and Flinn's quest to the ocean floor for the magic cutlass.

Most of the dinosaurs are realised by designer Max Humphries as subtle prosthetics, but T-Rex himself is a very effective full suit which looks just like the book's villain and proves expressive during lively sequences of song, dance and fighting.

Pleasance Courtyard, until 29 Aug (not 16), 10.30am, £9–£12 (£7.50–£10.50).