This story is excellent. It's not a *new* story by any means. Two people from warring cultures/classes/species/etc running away from the destiny that has been laid out for them. But it's told very competently and got me genuinely invested.
Animation and design wise it's beyond beautiful. Everything is so fluid. The characters have large areas of minimal detail on their bodies so when the detail DOES show up it pops out in perfect contrast. I want to point some special attention to the blood and water as well. It's gorgeous.
The show plays more like a two and a half hour movie than an actual SHOW. It's only five episodes long and I think it could have benefitted from one or two more. The pacing felt a little bit quick in places and I would have loved to see more time spent getting to know Fine and Momo before the inevitable plot hits the fan. I would also say the show is a bit too heavy handed in its metaphors and foreshadowing in one or two places. These flaws only knock one star off because, even when it was very obvious something bad was going to happen I was still interested in exactly how it played out. So it didn't necessarily take me out of the story.
Every other criticism I have is kind of a nitpick though the biggest nit I have to pick is I really wanted more worldbuilding. And I suppose wanting more is better than having everything overexplained and being disappointed by it. If you like vampires or stories about people on the run, or just REALLY pretty animation, give this a watch. You wont be disappointed.