Well, for context's sake, here's the rest of the query (which I'll also post in its own thread for crits, preferably after I figure out the hook):
Fifteen-year-old mermaid Rain is finally old enough to join her peers in the Harvest, their coming-of-age ceremony. Refusing to let her deafness keep her from becoming a siren, she plays the flute while the other young merfolk sing to lure humans to their deaths. What should be a day of triumph turns to one of tragedy when her cousin is poisoned by a human's harpoon.
The only cure lies in a distant sea, fiercely protected by the merfolk's queen due to its scarcity. Rain resolves to find it herself, and sets out with two other merfolk to guide her and be her ears. Humans are no threat so far below the surface, but the ocean depths hold dangers aplenty. While sharks and jellyfish are bad enough, even other merfolk seek to halt Rain and her comrades. They claim there's too little of the cure left to waste it on one merman.
Stealing the cure from the queen herself may be Rain's only option. If she does, she risks being imprisoned or even killed for treason. But if she doesn't, her cousin will die instead.