‘Nowhere Boy,’ about Lennon, playing at Magic Lantern

We’re so used to thinking of the Beatles and John Lennon as finished products – the band broken up 40 years ago, Lennon shot dead 10 years later.

How refreshing, then, to go back before the beginning with “Nowhere Boy” and see Lennon as a brilliant brat. A lusty, angry, quixotic, defiant, naive and yearning kid, without all the baggage that musical canonization placed on the guy’s shoulders.

Sure, things that were little incidents at the time – Lennon’s first meetings with Paul McCartney and George Harrison, his mom showing him how to play banjo – become momentous for the audience, knowing the musical revolution that this boy will help orchestrate.

Yet first-time director Sam Taylor-Wood and her collaborators do a lovely job carving out this formative slice of Lennon’s life without mythologizing or hanging a halo around the youngster’s head.

“Nowhere Boy” follows John from 1955 through his departure five years later for Hamburg, Germany, where the Beatles honed their music in marathon club gigs.

At times an eerie lookalike, Aaron Johnson (star of this year’s superhero comedy “Kick-Ass”) makes a wonderful teen John, capturing a mischievous rebel and a pained youth torn between the stern aunt who raised him and the sparkling mother who abandoned yet inspired him.

“Nowhere Boy” could have devolved into a superficial tug-of-war between schoolmarm Aunt Mimi (Kristin Scott Thomas) and flighty mother Julia (Anne-Marie Duff).

But working off the screenplay by Matt Greenhalgh – who also wrote the film biography “Control,” about Joy Division singer Ian Curtis – Scott Thomas and Duff create full-blooded portraits of the two women, each capable, in her own way, of bottomless love, petty spite and everything in between.

The moments that often resonate the most, though, are the Beatles scenes.

The re-creation of the first Quarrymen gig is a small thrill to watch. And while Thomas Brodie Sangster initially is jarring as McCartney, given that he bears no resemblance to young Paul, it’s fun to see the first two Beatles bonding and sparring as kids.

Given how Lennon’s life has been picked over by journalists and music historians, the film may not offer new insights into what made him the man he was. But it’s a sweet and touching love story to Lennon, and for many fans, that love is all you’ll need.