High-concept movies like "Frank" are at an automatic disadvantage.

No matter what steps director Lenny Abrahamson and screenwriters Jon Ronson and Peter Straughan have taken to make a serious film, the picture will be forever known as the one with Michael Fassbender in a giant, creepy papier-mache head.

This is a strange film for sure, but it's also a completely sincere and affecting one. Yes, Fassbender's Frank, the leader of an avant-garde band of angry misfits that reluctantly accepts outsider Jon Burroughs (Domhnall Gleeson) into their midst, never takes off that wacky disguise, but the movie has the courage of its convictions. It treats his character and the world he inhabits honestly, seeking to explore the source of the debilitating pain that landed him in this spot.

The movie painstakingly upends familiar narrative beats, taking the facade of a rags-to-riches musical story and completely shredding it. It's the story of a close-knit family of musicians most happy and at home when they're together, isolated somewhere in the Irish countryside working on music that's best left unheard by the outside world.

There's an off-kilter spirit to the picture; the characters are prone to sudden bursts of sadness and aggression and the screenplay propels them in sharply angled directions.

Frank's mask seems like it belongs in a slasher movie, but Fassbender's performance is a marvel, evoking extraordinary empathy for this sad, damaged man without being able to rely on his face, the actor's greatest tool. He subverts the movie's gimmick by laying bare the human inside the head.

Frank

3 stars

Directed by Lenny Abrahamson

Starring Domhnall Gleeson, Maggie Gyllenhaal, Michael Fassbender | Rated R