This book was dark, creepy, and fantastic. With a mixture of mermaids, old myths, and ghosts it was a major win for me! Going back and forth from 1872/1873 to present day, learning what really happened and also watching Hester try to uncover the mystery of her curse was so great. I really loved how they merged together. At times I thought that maybe some of the writing was a bit mature for YA, but I did read an ARC for this review and some of the more mature content could have been removed. Putting that aside this was an incredible book. The characters were well developed and the way the story flowed, even with jumping back and forth, was great!Since we go back and forth we have two main characters. Syrenka (or Sarah) and Hester. I liked them both. Syrenka just wants to find love and be happy. She has a few unfortunate situations and they eventually lead to a family curse that passes from generation to generation. Now Hester wants to discover if there is a way to stop the curse short of never loving or having children. As we discover the things that Syrenka goes through, in present time Hester is slowly starting to unravel the past. Hester was a great character. You could feel her desperation the deeper into the situation she got. The only thing I didn't like was how she really started to just be flat out mean to the people around her and it was like the only thing that mattered was Ezra. I admired her strength to do what she had to though. This story is dark. It has some more mature content in it and some pretty gross scenes. (The more gory the better for me!!) I really enjoyed the darker tone of this book. It really created a fantastic atmosphere that was easy to get swept up in. I loved how things really connected. The writing was fantastic too. I felt that the settings were described really well and I could see myself in the book along with the characters. It's funny how when I really enjoy a book sometimes I just don't know what to say. I feel that way about this one. I don't want to really get into it because I don't want to give anything away. If you are looking for a dark read that doesn't hold much back, this is definitely a book for you.