Named for the Greek goddess Mnemosyne, goddess of memory and mother of the nine muses, the Xebec/Genco collaboration is a six-episode* TV special based on Hiroshi Ounogi and Chuuou Higashiguchi's light novels. The story revolves around a pair of (seemingly) young women who are actually immortals and who run a detective agency. Although the two-- leader Rin Asougi and the child-only-in-appearance Mimi –attempt to lead relatively normal lives, their cases always lead them back to their dark pasts and their unusually immortal existences.
It's a pretty cool show before you add in the gore, which is more than enough to potentially make or break the show for you (depending on whether you like sexually-charged torture in your anime or not). If you're not sure, it's well worth giving a shot...just don't bother if you've got a weak stomach.
* EDIT: Just heard back-- the original Japanese version was six double-length episodes, which have been split into 12 regular-length episodes for the release.
That said, FUNi did pick up Claymore and Shigurui, which are also both pretty violent.
It's the truth. Just saying.
But this is a very good 90s-style anime OAV made recently, if that's your thing. I will pick it up for sure.
The 12-episode thing is kind of odd. Why did they say it's 12 when they didn't have to?