I don't know how essential this latest installment in the X-men saga is. After all, there has already been several cartoons here stateside involving everyone's favorite mutants. But, I suppose it can't hurt to try to take Japan as well. It's a little odd though, because while faithful it's also off in odd ways. Just in the grammar of body language it feels just a little wrong. Specially the character of Wolverine who is played more like the ronin in the classic version of "The Seven Samurai."
The basic plot is that the X men are called to Japan first to find a little mutant girl and then to solve some bigger mysteries like why does the Professor's mutant detector doesn't work in that area of Japan. There are some bad guys named rather cheekily "U-Men" who look nothing like humans. They are robot/cyborgs who are interested in harvesting mutant organs. They save the Japanese girl and Emma Frost who both join the team. The girl, Hisaki, is a brilliant little piece of patching two cultures together. Her mutant power is basically creating a psychic mecha. So we have our giant robot even though this is an X-men show. The animation is smooth and impressive. I like how they handled the Beast. The big mysteries are little "meh" but the action is pretty spot on. Cyclops is still a massive buzz kill, but what can you expect?
Overall, worth a watch.