Bay of Sighs is the second book in the Guardian Trilogy. The first book, Stars of Fortune, was okay, very similar to the O'Dwyer trilogy, but the characters were different enough that I enjoyed it. 
 Now we have the second pairing looking for the Water Star, Annika the mermaid and Sawyer the time traveler. They are likeable enough, but I didn't feel their characters developed much, especially as Annika was very childlike and Sawyer just kind of a good guy. I especially had trouble with one scene where they have sex, but Annika is wearing her tail. It was just weird, not romantic as Ms. Roberts usually writes. 
 I want to see how the next book ends, but this is definitely not my favorite series by Ms. Roberts.