Noir is the latest anime to join the ranks of 'anime-by-numbers'. Cute girls have guns, cute girls kill the bad guys. Nothing new here, but Noir does do it very well, and different from your normal anime.
Mireille is a hired assassin, a lady capable of dealing death to multiple people without even breaking a nail or getting a hair out of place. She is quickly joined by Kirika who seems to have selective memories and likes to dress as a schoolgirl. Kirika seems to have the same ability as Mireille, but she knows nothing of where she got her skills from. Mireille teams up with Kirika when she is shown a locket, something which Mireille remembers from her past.
Noir has the awful habit of re-using footage at every opportunity, though it does seem to be trying to get you to understand an important plot development. Unfortunately you understood this the first time you saw the footage. Noir attempts to create the same atmosphere as many of the old Art house European noir movies, it succeeds and fails in equal measure, but that doesn't matter as Noir is attempting something different.
There are some excellent gun shoot outs, an example would be the darkened casino in episode 3. Noir's stories are not groundbreaking but they are enjoyable and you will find yourself caught up in the mystery. A special mention must go to the music. Noir has a wonderful haunting soundtrack, which only helps to make this anime even better.