Not only is this story line original, but it's also an action-packed tear-jerker. The twists and turns in this story are phenomenal! You think you know what's going to happen when, BAM, something else happens. Its' exciting and drawn out flawlessly. I highly recommend this anime. It's got everything you could ever want and then some.
Watched it years ago, still remember it! Was trying to find it here on Crunchyroll. I had the discs, have to go look for them now. This series is fast paced, fun, action packed with a good story twist! Loved it. More impressionable than typical anime series that I've seen.