I really like the story and I would give it a 8 In general. Why? I saw many negative comment about this manga but personally I think this manga deserve better than that.This manga is really underrated, I came here because I really love Yuyuko Takemiya story (Toradora!, Golden time...).

It is true, the ending is not what we expected, the ending is not very clear. They were hiding their relationship but for what reason?
1. Because they are brother and sister so it would be very awkward if people know brother and sister were couple?
2. Because they are still couple, they still love each other but they doesn't want people to know about it since they are brother or sister?

The ending wasn't clear enough to let us know the truth but that's very nice of it. Some people prefer this ending and some people prefer the other. The 1. is very realistic, the 2. is a happy ending so it depends the taste of readers.

What's a bit unfortunate is the story is a bit too short, I would wish to have more detail about them both and there's some small thing a bit confusing, the part where Niki ( with a mask) kill Niki (kid) in Hotaka's dream. Really not sure what's he trying to tell us.

In conclusion, I really love the idea of the story, I love the way it ended, the art is great but it was a bit too short and some part was a bit hard to understand