Headlined by Michael Fassbender in an odd and humble performance, Frank is an ode to the creative spirit at its most imaginative and destructive.

It’s one thing for an actor to portray a character who hides behind a mask. It happens all the time in superhero movies, yet Batman and Spider-Man have alter egos underneath those masks, and with it comes face time for the actors portraying them.

That is not the case with Frank, a mad musical genius who wears a large papier-mache head and exudes an intoxicating influence over his eccentric pop/alternative band of misfits, the aptly named “Soronprfbs.” Playing the role is Michael Fassbender, an actor who has steadily raised his profile to A-list status thanks to his prolific output that includes 12 Years a Slave and X-Men: Days of Future Past.

The Frank character itself is inspired by Frank Sidebottom, a creation of comedian and musician Chris Sievery who reached cult-status during the ‘80s. Much like Sievey’s creation, the Frank of this movie is a mystery yet one of magnetic charisma. That is thanks to Fassbender, who although essentially faceless still manages to captivate with that screen presence of his projecting a certain aura.

Captivated by his spell is John (Domhnall Gleeson), a songwriter struggling to find his song, who eagerly agrees to become Frank’s new keyboardist.

With Frank an emotionally stunted character, John is our “in” into Frank’s world as they and the rest of “Soronprfbs” reside in a remote shack to write and record their first album, John taking in the madness and romance of a bizarre situation that is often funny in a dark, slightly off kilter way that brushes with tragedy the more John attempts to look under Frank’s guarded veneer. After all, every mad musical genius – from Mozart to Daniel Johnston - is driven by a darkness of some form.

The casting of Gleeson as our conduit is perfect, given that he has an incredibly likeable screen presence. There is an innocence about him that compliments the stuck-up attitudes found in the rest of the characters, especially Maggie Gyllenhaal’s vamp, Theremin playing member of the band whose stare is sharper than her blade (which she uses with extreme prejudice).

The best moments in Frank are those that focus on the chaotic creativity which Fassbender’s masked madman conducts with swaying, organic fervour. Director Lenny Abrahamson wisely chose compositions that are catchy enough to get stuck in your brain, yet weird enough to suit the avant-garde aesthetic of its characters.

There’s nothing worse than watching a film about musicians to find their music…well, sucks. Frank doesn’t have that problem.

Combined with the strong performances, askew yet effective comedy and compelling mystery as to who or what this masked guru of rock is, Frank is as compelling a film about music and its mad masters as they come.