This anime has a great action plot with twists. Hei is an awesome character, he is a kick-butt assassin with no mercy. The second season has a pretty good plot also plus the relationship that builds between Hei and Yin is interesting since it was said dolls don't have emotions (WRONG lol ) but the way it ends in total kinda bums me out. Anyway, I would recommend DTB; when you watch it, you wont regret it.