Bloodlines is the first novel in Richelle Mead's spinoff, featuring some of the minor characters from her previous Vampire Academy series. It's obviously meant to work as a new starting point into the paranormal fantasy world Mead's created, but I suspect it works better if you've read some of the other Vampire Academy books as well.
Sydney Sage is an alchemist, part of a secret organisation which has worked to hide the existence of vampires, both Moroi (living "nice" vampires) and Strigoi (undead evil vampires), from humans. She's been rigorously trained for her duties since she was a child by her very strict father, and alchemists in general fear and try to avoid vampires as much as possible Due to events that transpired in the final two Vampire Academy books, Sydney's seen as someone who fraternizes with the Moroi vampires, and has forgotten her place. Yet when the only sister of the ruling vampire Queen is in danger of being assassinated, Sydney seems to be the best alchemist to help keep her safe and in hiding, as she's familiar with the girl, and young enough that she won't seem out of place in high school.
Sydney's happy to get a chance to work again, but horrified by the thought of having to share a room with and pose as the older sister of a vampire, albeit a Moroi one. However, if she refuses the mission, she'll be cast aside and replaced by her younger sister, who will have to work with an alchemist Sydney knows is a creep, so she agrees to go to high school in Palm Springs, and share a dorm room with a living vampire, helping to keep the girl safe. Already having learned that the Moroi vampires and their half-human servants/bodyguards are not so bad, Sydney becomes more and more open minded as her mission progresses.
At the school, she quickly makes a lot of friends, and discovers that while she excels academically, having been home schooled, she's got a lot to learn when it comes to social interaction. She also discovers that someone is giving the rich high schoolers performance enhancing tattoos, very similar to those of the protective tattoos given to the alchemists. Whoever's doing them is clearly doing something illegal, and Sydney tries to figure out where the tattoo parlor gets its supplies, while trying to fend off her hostile and scheming supervisor and organizing the lives of her vampire charges.
There's a lot of potential in Bloodlines, but compared to even the weaker Vampire Academy books, it falls a bit short. This is partially because Sidney is not as engaging a protagonist as Rose Hathaway was. While there is some action and mystery in this book, it's also not as exciting and fast paced as some of Mead's previous novels, and the story drags in places. The main reason I enjoyed this book was the return of Jill and Adrian from the Vampire Academy books, who were always interesting there, and get more to do in this book. I'm also curious to see where Mead is taking her spin off, she doesn't seem able to entirely distance herself from the characters of her previous series, and I hope that she's able to make this work on its own, otherwise I think the books will suffer more in comparison.