This is the sequel to When the Sea is Rising Red, which I thought was one of the most interesting YA books of 2012. Pretty much the only problem I had with WSRR is that I thought the story was beyond the age description. Not that it was too much for a YA audience, but the world-building, character conflicts and social themes were good for a wide range of ages.
House of Sand and Secrets starts a few months after WSRR, with Felicita and Jannik in MalllenIve with more than just space between them. One of the things that I found most interesting about WSRR is how, while Felicita isn't a terribly likable character, she's compelling and I never wanted to stop reading even when her behavior bothered me. While Rising Red is arguably the story of Felicita figuring herself out, House of Sand and Secrets is the story of her trying to be the person she's become. It's harder than it sounds, with societal pressures and rampant misogyny and nobody to lean on or guide her.
I like the person Felicita's become. She's not perfect, in fact far from it, and her ambition and her guilt drag her into a sinister series of violent crimes against vampires. Which brings us to Jannik. I'm a sucker for a good vampire, and Jannik is a great character (not to mention Hellisen's vampires are unique and interesting). He's floundering much like Felicita but exhibits it in different ways. Their styles of communication and apprehensions about each other push them away from each other even as the leaders of MallenIve's Houses shove them together.
The pacing of the story is excellent, giving the reader enough breathing room at the beginning to start to understand the players and the rules of the world. As the action ramps up, each decision and act or failure to decide or act has consequences. Hellisen plays the characters - each with their own complex motivations and nuances - off of each other masterfully. I don't want to give anything away, because the story was full of unexpected twists and depths. While the plot was satisfying, it was watching the characters establish themselves and revolve around each other that's the most memorable part of the story. Felicita and Jannik are excellent characters separately, but they're magnetic together.
I love this universe, and very much hope to see more stories set in it.
ETA: While When the Sea is Rising Red was marketed as YA (I'd argue it wasn't), I would consider House of Sand and Secrets more of an adult book due to themes and content.