Darker Than Black

Darker Than Black is an action anime series with a sci-fi bent to it. It's from Bones, a studio that has produced some very good anime including the Cowboy Bebop movie, Fullmetal Alchemist, Ouran High School Host Club, and Jyu Oh Sei (which was covered a while back on HFG).

The main character of the show is Hei, an assassin who pretends to be a student named Lee when he's undercover. I have only seen the first episode, but I'm interested in seeing more. Funimation Entertainment will be releasing the show sometime this year.