This manga is inspired by a story from the video game Sinoalice so if you like the game it is a highly recommended read.
Played the game or not, its a confusing story, its clear that its done on purpose for the intrigue of whats happening. But the events are a bit...random so i cant say it has a GREAT story.
But i really enjoyed reading it, the story is very disturbing and it managed to made me have an unpleasant feeling the whole reading, a mixture of sadness and intrigue
So in conclusion if you are looking for a happy story this is not your manga, otherwise give it a try.