This episode is visually amazing. It's just a pity that the story is so boring, and the dialogue so bland. I sat there, entranced by the incredible use of colour and line work, as tedious expository dialogue flew in one ear and out the other. Because I was so uninvolved by the plot, I'm not entirely sure exactly what happens. But here is what I gathered:
There's some ninja, and he fights a woman for some reason. Batman cares because... the woman was his old sensei's new protege or something. He flies to Japan, and the ninja steals a map to some ancient fighting instructions that are hidden in a cave (because they were just too damn deadly or whatever). Batman follows the ninja to the cave, but the instructions had deteriorated with age, to the point that they crumbled when they were touched. There was a big enough piece left to teach the ninja some sort of death blow or something, though, and so... Batman... [scene missing]... Batman and the ninja are fighting near a volcano, and the ninja uses the death blow, but Batman was prepared because he had seen the ninja's training dummy and so knew were the death blow was supposed to land (or something like that). Batman beats the ninja, and then it was the end? Oh wait, no, then Batman's sensei said... something... about how Batman... wasn't a ninja? How he was a samurai? Or some shit like that, anyway.
I don't know if any or all of that is correct, and I don't really care. I enjoyed this episode visually, but it was just... tedious in all other respects, sort of like a bad Tim Burton movie. I think this is partly caused by the fact that the episode was directed by Bruce Timm, the producer of the show, who seems like much more of a visual guy than a story guy. I love Bruce Timm and all, but he needs a really solid script (like Heart of Ice or Mask of the Phantasm) to do actually properly good directorial work. Otherwise you just get very pretty tedium.