This is a prequal one shot that takes place between the manga Blood+ Adagio and Blood+.
This is a Hagi solo story, so Saya isn't part of it since it takes place after them separating in Vietnam.
The art style is different than the other two manga series because it was drawn by a different manga artist.
I was confused when the description said it was geared more towards girls.
After reading, I get it.
It was drawn in a shoujo style and having "tropes" with the shoujo art style like having sparkles in the background.
It's not a yaoi manga, but there are definitely teases to
fuel a Fujoshi's imagination.
This is a story that focuses on Police Officer named Nishi who encounter's Hagi when investigating a crime scene where a victim was found completely drained of blood.
Hagi is more vulnerable is this story.
Not only is he physically weaker because he's scared to drink blood, but he misses Saya.
He feels horrible for leaving her behind and wants to find her.
Which is why he's in Hong Kong, he's hunting down Chiropterians in hopes of running into her.
This was a pretty okay story, but I honestly wouldn't recommend it to Blood+ fans unless they really cared about Hagi.
Honestly this was a satisfying answer to what Hagi was doing during his separation from Saya.
Unless you're a really huge Blood+ fan and want to read everything tied to the series or you're a big fan of Haji there's no harm in skipping this.