So I started reading Lies Beneath by Anne Greenwood Brown...

Goodreads

Pavati drew closer, putting her arm around my  my shoulders. "Get invited to the huse, Cal." Her breath was still warm from the Mississippi Delta, and her full lips brushed my ear as she said, "Meet the parents. Be the boyfriend." I nodded. The proposed seduction played out in my mind like a movie —the fake smiles, the deceitful kiss...  "Get Jason Hancock to trust you," Pavati continued. "Tell him you've never been fishing. Let him invite you out on the lake."  I closed my eyes.  "Then we'll show up," she said brightly.  I pictured the three of them transformed, circling the boat like sharks, their lithe bodies cutting through the water, then slinking over the rail.  "Then what?"  "He'll beg for mercy. He'll ask us why," Tallulah said, her voice ringing. ...  "And then we'll take him down." Tallaluah leaned her head agaisnt my shoulder.  "Slowly," Maris added." We'll let him come up for air, and then we'll drag him down again."

Killer mermaids!! These mermaids are not your garden variety mermaids, they are creepy and vengeful. Which is actually one of the things I like about this book. They are just so screwed up.
On the other hand there are things that I don't really like, like for example the one lonesome POV. We read the book from Cal's POV, but I think the story would have been better with the girl's POV as well, Lily's. That's the daughter Cal is supposed to get close to in order to kill the man they want to kill. It's a pretty sick plan, and I am not sure if I am going to be able to go along with the obvious romantic relationship that is going to bloom between Cal and Lily. One thing is for a guy to be a predator that falls in love with the prey, another thing is for a guy to be a predator that falls in love with the prey when he is stalking and learning everything about in order to lure her father into the water and kill him.
That is just sick, and maybe a bit too much for me to swallow.