Ninja (2009)

Casey, who was abandoned by his mother as a child, is taken into a dojo and trained as a ninja. His jealous rival is kicked out for not following the ways of the dojo and ends up on the path of evil becoming a for hire assassin for immoral business men in a secret society.

Casey's master entrusts him with a sacred box, which he must guard until it gets into the right hands. But the secret society wants this for themselves and Casey must engage in a battle with his old rival.

There is also a female ninja who doesn't appear to have been serious about her training since she is constantly fainting or being rescued by Casey. This is convenient since she is his love interest, but otherwise serves no purpose and doesn't fit with the background story.

This is essentially an updated version of the 1980s ninja films. It's a fun action movie with decent fight scenes and a cliched plot. It's pretty good if you like that sort of thing. If compared to the recent Ninja Assassin, I would pick that movie over this one.