Legend has it that King Arthur is not dead, just sleeping, till the time comes for him to regain his throne and restore his nation to its former glory.

Something like this faith underlies Joe Cornish's fantasy adventure The Kid Who Would Be King, set in a gloomy version of Britain ― either a dystopian near future or the dystopian present ― where heroes are in desperately short supply.

Cornish's 2011 first feature Attack the Block was a mash-up of science fiction and social realist teen
movie, involving an army of menacing extra-terrestrials descending on a South London council estate.

This time around he's aiming for a younger audience but borrows from an equally diverse range of sources, from 1980s Hollywood favorites like The Goonies and The Terminator to classic English children's books like The Sword in the Stone.

Bullied at school and yearning for his long-lost dad, the twelve-year-old hero Alex (Louis Ashborne
Serkis) finds solace in a book of Arthurian legends while aiming to live by his own knightly code.

Still, even he is startled when these stories start coming to life in the present day. Could the sword he pulls out of a stone on a building site be the original Excalibur? And can he trust the weird new kid at school (Angus Imrie) who claims to be the ancient wizard, Merlin?

What is clear is that adventure is beckoning and that Alex is not the kind to turn it down. At least
symbolically, he really is King Arthur, using a gift for oratory to win over his foes as his precursor was able to unite Britain's warring tribes.

Before long he's leading his followers to Cornwall on a double quest ― to make contact with his father, and to prevent the enchantress Morgana Le Fay (Rebecca Ferguson) from unleashing darkness upon the world.

By the standards of modern children's films, The Kid Who Would Be King is a breath of fresh air, a one-of-a-kind passion project infused with its maker's evident pleasure in spinning a tale.

Cornish knows how to stage a sight gag ― there's a good one involving an updated Round Table ― and how to weave pop culture references into the dialogue without departing too far from the kind of thing kids might actually say.

Most of the strongest moments are in the first half, where the relaxed pace leaves maximum room for comedy and for imaginative digressions, such as an explanation of the real purpose of Stonehenge and a battle that pits Alex and his gang against a grove of enchanted trees.

The breakout star here is Imrie, whose foppish theatricality is assured enough to suggest that he has a solid half-century of eccentric character parts ahead of him.

Up till near the climax, the film maintains an intriguing ambiguity, hinting that Alex, well-intended as he is, maybe fundamentally mistaken about the nature of his mission, as well as about who to trust.

A good liberal on the surface, Cornish takes care to spell out that even supposedly timeless myths shouldn't be accepted uncritically; Alex's leadership qualities, for instance, don't derive from literal royal blood.

But in the end, The Kid Who Would Be King adheres to its own version of the “hero's journey”
formula ― and, like Attack the Block, proves less substantial than might have been hoped.

Morgana is more a plot device than a convincing representative of evil; the logic that identifies Alex with the original King Arthur is never very clear; nor are the stakes of the final showdown, in part because realistic violence has been ruled out of bounds.

All the same, the film does bear a political subtext, if a slightly disconcerting one. The implication isn't that anyone can be a hero, but that some people are natural heroes while others are natural sidekicks ― like Alex's friend Bedders (Dean Chaumoo), who cheerfully compares himself to Donkey in Shrek.

In truth, there's an authoritarian streak in Cornish somewhere, manifested most openly in the running gag of Merlin using hypnosis to overcome the clueless adults who get in his way. However far Britain may have fallen, is it really helpful to propose, even in fantasy, that its problems might be solved by a new king?