This book was a really pleasant surprise, I'm glad to say. I've been reading it all morning through and just finished it. :)Of course, it sounds just like your typical supernatural romance YA novel. But what I really liked was that this was just if you took it at face value.The story is about a jittery girl named Vanessa, whose sister Justine dies cliff-diving/tombstoning while they're on holiday in coastal Maine one summer. Shortly after that, Justine's boyfriend Caleb goes missing. While her mother and father take her back to their hometown of Boston, Vanessa is determined to get to the bottom of this case, which isn't as open-and-shut as the police are making it out to be.She drives back to Winter Harbour, hanging out with Caleb's older brother Simon, and makes friends with the staff at a local diner - the incredibly friendly Paige, her irritable older sister Zara, their mother Raina, and Grandma Betty, who was recently involved in a terrible accident where she swam out to sea and got struck by lightning.More and more strange murders begin to occur, and when Vanessa discovers a scrapbook Zara is keeping, which chronicles her love life... with all the men who have gone missing or been murdered, she can't help but feel a little bit suspicious. An old man who frequents the diner, Oliver, is a local historian, and still in love with Betty after all these years, but still suspicious of her family.Vanessa, Simon and Oliver are going to have to work together if they're going to find Caleb and work out the mystery of the family, who Oliver suspects to be mermaids...Yep, you heard me right, murderous mermaids à la Pirates of the Caribbean: On Stranger Tides. However, rather than the 'I get human legs if I set a fin on land' mermaids of that movie, these are just sirens sans fish-tails who call men and women to their deaths after getting them completely infatuated.Oh, here's a spoiler as well: our main character, Vanessa, is actually a siren herself. Her father bonked Grandma Betty's sister, and when she died in childbirth, 'Big Poppa' took Vanessa with him to his previous marriage and little girl Justine, somehow managing to assimilate her as his own flesh and blood. No, there's no explanation as to how Justine's mother wouldn't quite be so keen on her father showing up with an unexplained newborn baby like he'd just bought the family a surprise puppy or something.Vanessa decides to conquer her fear by allying with Betty and Paige, who also have their own reservations about Zara and Raina. She dives off the same cliff that killed her sister, and activates this... tank that freezes the entire cove where the sirens drag the men to their dooms.And the novel ends with Vanessa in hospital, reunited with her parents, and now, thanks to her siren heritage (which I'm guessing is matrilineal) she has to consume salt water to keep alive. Rather than those of us who have to ingest it to be sick during illnesses.Sirens have a pretty weird explanation in this novel... Okay, so it's rather refreshing that they're just pretty humanoids who have wondrous singing voices and can breathe underwater, but basically, once they come of age, they get ceremonially dipped in salt water, after which they need to constantly bathe, drink, or swim in it lest they dry out like prunes and die. Okay...Anyway, it was a very compelling read, but towards the end it got a bit rushed. I also thought that the 'finding Caleb' subplot was a bit overlong, and the big old weather conundrum that was baffling meteorologists and making Simon rush up and down the Maine coast (which, by the way, reminded me a heck of a lot of nearby Cornwall) collecting samples from rock pools and measuring tides and currents... was just described away as some kind of a fluke by the end. Sigh.However, I did like how it didn't focus too much on the romance between Justine and Caleb and Vanessa and Simon. It was more about solving the mystery of the strange murders with the help of the local historian and other onlookers. The ending may not have been my cup of tea, but it did just fine for a standalone novel. 3.5/5.