I suppose there is an argument to be made that “Nowhere Boy” could be enjoyed as a psychological study of a deprived teenager struggling with his identity and his very complex relationship with a distant mother.

It is that. But it is also, unavoidably, the story of John Lennon, one of the definitive artists of his time, and as such the story has a frame around it we can’t ignore.

How nonBeatles fans will take this film is unknown to me, but it is a touching and earnest coming-of-age story on its own and a shrewd portrait of future genius.

The word “Beatles” is never mentioned. The action takes place mostly in the late 1950s, before the band found itself, and (for most of the film) before Lennon had met his partner in song, Paul McCartney.

The young John is well played by Aaron Johnson, a British actor who made an amusing impression earlier this year in “Kick-Ass.” A Liverpool lad, John is being raised by his Aunt Mimi (Kristen Scott Thomas), because John’s father has wandered off and his mother is a somewhat unstable personality.

Violent and unfocused, John casts about for some kind of lifeline. Music provides one; and his mother, with whom he tries to re-establish contact, might be another.

Mercurial and something of an arrested adolescent, John’s mother Julia (Anne-Marie Duff, recently seen in “The Last Station”) is a dangerous figure for a sensitive, angry kid. Lacking boundaries of intimacy, she manages to confuse her son even more than he already is (for more on the subject, see Lennon’s nakedly autobiographical song “Mother”).

For Beatles fans, the sacred text really begins to get written around the time John and his skiffle-band mates play a church picnic and a mutual friend introduces a guitar player named Paul McCartney (Thomas Sangster, the boy in “Love Actually”), who knows the chords to “30 Flight Rock.”

And the rest, as they say … well, not quite history. “Nowhere Boy” wisely stops short of anything like the big time, as it keeps the focus on John Lennon’s youthful family woes. In that sense, director Sam Taylor-Wood has crafted a well-turned domestic drama, steeped in Liverpool atmosphere and fine acting (Johnson is more than credible, and Duff has some electric moments as Julia).

If it weren’t about the future Beatle, all of that might be admirable enough, but not earth-shaking. But the movie is about John Lennon, and so it becomes another piece of the mosaic forming around the band’s mythology; other worthy entries are “The Hours and Times” and “Backbeat.” On that score, it’s an absolute keeper.