Because the plot is convoluted nonsense and the paper-thin characters are treated with less reverence than victims in a low-rent slasher movie, the title pretty much explains it all. "Ninja Assassin" is about a young man, Raizo (Rain), trained to the point of harsh physical abuse as a child to become both a martial arts expert and a killer. Now an adult holding a very special grudge against the cruel dictatorial master, Ozuno (Sho Kosugi), who trained and tortured him, Raizo turns the table on Ozunu's minions while edging ever closer to the monster himself. Along the way, Europol agent Mika (Naomie Harris) gets mixed up in Raizo's fight.

What else needs to be known about "Ninja Assassin?" That director James McTeigue has stepped down and taken a full-out tumble from his first film, 2006's provocative "V for Vendetta," and screenwriters Matthew Sand (his debut) and J. Michael Straczynski (2008's "Changeling") needn't have even bothered showing up. Following a mysterious prologue involving the arrival of black sand acting as harbinger for gruesome death and cleanly sliced body parts to come, the film has already prematurely given up most of its flashier money shots. What follows is laughably convoluted exposition between Europol partners Mika and Maslow (Ben Miles), flashbacks to Raizo's torturous childhood and his friendship with Kiriko (Kylie Liya Goldstein), and then a full hour of chaos signifying nothing.

Action-packed and nearly incomprehensible, the picture devolves quickly into an array of shaky cam, epilepsy-inducing editing, and blatantly fake CGI bloodshed the color of red paint. It looks like it was created on a 1980s-era MS-DOS art program. Sympathetic as a kid, the adult Raizo is a blank slate of unreadable emotions and no charisma. Korean pop star Rain, who actually impressed in a supporting role in 2008's "Speed Racer," proves ill-equipped to carry an entire motion picture on his shoulders. There is no depth to what he does with Raizo, but, then again, there's no depth to anything found on the screen. As Mika, Naomie Harris (2008's "Street Kings") is likable and quite a lot better, but above this material. No one could make the kind of asinine dialogue she has to spout sound natural. None of the other actors warrant mentioning by name, though it is curious to note that the film is set in Berlin, stars a predominately Asian cast, and the only language ever spoken is English.

With nothing to care about or identify with, the hectic ADD-afflicted action paves the way for repetition, gore galore (that, again, never looks remotely real), and out-of-the-blue plot developments that don't even try to make sense—even within the narrative's strained logic. By the time the climax arrives and ninjas are literally evaporating into thin air and reappearing on the opposite side of the room without explanation, all the viewer can do is just throw their hands up in defeat and eagerly await the end credits. Those who hold out that long will be rewarded with the movie's funniest moment. After Raizo climbs triumphantly to the top of the wall that bordered the hellish Berlin orphanage he stayed at as a kid, the other side reveals a landscape that better resembles the fantastical, sweeping Middle Earth of "The Lord of the Rings" than Germany. It's so ridiculous you have to laugh. Unfortunately, the remainder of "Ninja Assassin" cannot make the same claim. It's silly, all right, but also so ceaseless and empty that it fast turns into a bore.