In this murderous twist on The Little Mermaid, alchemist Red discovers that true love can be more dangerous than it seems. It'll take the help of her friends to answer the question . . .

. . . when devotion has a deadly price, what does it take to keep your head above water?

Red and her magical talking dog, William, are looking forward to a vacation. They're spending the first days of summer in Seaside, a quaint beach town, to celebrate the wedding of a merfolk friend. But when the groom's father is murdered during a pre-wedding feast, all that love in the air turns sour.

Of course, when Red's friends ask her to help them investigate, she immediately agrees. But despite her best intentions, there's something about this mystery that has her feeling like she's in over her head. Was the murderer angry about the marriage between merfolk and human, or perhaps scared of an old prophecy coming to light? Was it a vengeful sea witch out for a blood price-or was it an eco-terrorist? When Officer Thorn shows up as a special police guild detective and Red finally learns to lean on her friends (including a few more surprise faces from Belville!), it's only a matter of time before the answer washes up.