It's Easter and the Everyman Rep is taking on its third production - an adaptation of Brian Patten's 2001 children's novel on the power of storytelling and friendship. God knows we could all do with a little of it in 2017.

Structured as a portmanteau, The Story Giant is an intriguing proposition. A giant as old as time who collects stories is joined by four children - a Scouser, a loud American, an Indian and a Syrian refugee (in a tweak to the original text) - who assist the him in trying to locate an elusive final story by enacting folklore, legend and whimsy, lest his fantastical dreamscape library fall to bits.

That sets up for a whistle stop tour around history's greatest yarns and the four word-hungry children assume and discard characters as they act them out. All the adult cast turn in committed performances as children not yet in their teens. Tom Kanji as the Syrian Hassan pitches it perfectly while Melanie La Barrie's loud-but-lonely LA girl Betts gives different moments both welly and tender notes.

As the titular giant Richard Bremmer bookends the play in hair-tingling monologues, equal part Doctor Who and Dumbledore (the latter acknowledged in a musical motif). But for a story about the power of books and the imagination, Matt Rutter's play often feels finger-waggingly proscriptive, The Giant more akin to a dusty schoolmaster as he embarks on another lecture.

Somewhere between script and direction something goes astray - The Story Giant feels a little leaden and it's occasionally unclear what is happening. And who knows what the kids make of Tommy Cooper, Barry Hines and Lady Bracknell references? Perhaps in a different context a child might make sense of them. In a play they seem destined to whizz over their heads, as do the rather starchy monologues on the value of books.

It's a production that seems to acknowledge the fact that children have to be encouraged, perhaps gently coerced, to read. How much power does the written word hold for kids in a world of endless TV, internet and smartphones? One wonders if the same could be said for attending the theatre against a backdrop of constant partial attention.

Cushions that place the audience's kids in amongst the action and a huge tree at the centre radiating outwards are nice touches, inviting everyone in. But the encircled set doesn't always work in the actors' favour. The theatre-in-the-round ensures that they intermittently turn their backs to the audience and can be hard to hear, while the tree obscures their faces.

These issues ensure The Story Giant drags in the first half, with little sense of threat or urgency. It's a shame as the second half is pacy, funny, creepy and features a lovely moment that undercuts its own occasional pomposity, when the Giant - older than history, hewn from the mountains, sitting in his impossible library - is asked what aromas he can scent.

"Knowledge," he replies and the cast (and audience) roll their eyes.

"And farts," he admits. And everyone laughs.

In moments of such irreverence The Story Giant clicks, with some clever soundscapes and lighting assisting the cast in spirited re-tellings of a number of stories that all seem familiar. Oddly enough Patten's book - adapted here by Lindsay Rodden - brings to mind Anthony Minghella's 1987 television series The Storyteller. Certainly anyone familiar with it will see the conclusion a long way off, but the journey is the thing and when it gets it right the tight cast make the material sing.

In the end it comes good but it still feels flabby as a production: overlong and over-earnest. With a tighter grip and tauter narrative The Story Giant might have been a fitting last piece of the jigsaw in the big feller's library. This new production still feels like it's missing a couple.

The Story Giant runs at the Liverpool Everyman until 29 April.