Obsession, in its many shades, has long been the keynote of Werner Herzog's career. From Dieter Denglerthe real-life hero of the documentary Little Dieter Needs To Flyto the wide-eyed monomaniacs played by Klaus Kinski, the typical Herzog protagonist is ruled by a single-minded drive, with all other concerns taking a backseat. Invincible, Herzog's first non-documentary film in some time, breaks with that pattern, offering a hero devoid of the obsession that consumes those around him. A historical figure who has become a subject of folklore, Zishe Breitbart lived as a shtetl blacksmith in Poland before he became a performing strongman in a Germany that was slowly giving itself over to the Nazis. Here, Breitbart is played by Jouko Ahola, a retired two-time World's Strongest Man titleholder from Finland, capable of lifting 900 pounds. The star of the film and the center of virtually every scene, Ahola gives a performance that's often touching in its unpracticed simplicity, and just as often distractingly flat due to his Arnold Schwarzenegger-esque emotional palette. Still, this is an extraordinary story uniquely suited to Herzog's abilities, and it eventually becomes easy to accept Ahola as a nearly mute witness to the obsessives around him, most immediately Tim Roth in a striking performance as Ahola's employer, a self-proclaimed master of the occult. Putting on a nightly show that's part burlesque, part circus, and part Nazi propaganda, Roth tailors his performances to his audience's fascist sympathies, dressing Ahola up as a blond strongman and delivering prophetic predictions of Hitler's rise to power with an unblinking gaze that defies anyone to deny his connection to the powers beyond. It's a scam, of course, driven by an unwavering desire for wealth that mirrors his audience's desire for power. Ahola's growing resistance to his employer (first onstage, then off) gives shape to an often aimless and ultimately disappointing film that nonetheless features no shortage of classic Herzog moments. Each time the focus shifts to the performance sequences, particularly those featuring Roth, the film finds an energy its other sections can't match, as if Herzog better understands those who obsess, for good or for ill, than those who try to stand in their way.