Spoiler alert I'm going to be very honest. I don't think I can give a good review without being spoilery. So, if you're not into that read the book and then read this. I thought this book was going to be mostly the submersible race. It was not. The book starts with Leyla, a girl who has spent her life underwater after water covered the earth after cataclysmic earthquakes. Leyla has never left London and is trying to get her father out of prison. She ends up basically road tripping it with a  Friend of her grandfather's friend. In all honesty, I could see this being the entirety of the book and I'm so glad it's not. There's a lot in this about bigotry, fear, and Othering. This one does end on a cliffhanger.