Hazel Bly used to have the perfect family. But when a kayaking trip goes horribly wrong, Mum is suddenly gone forever and Hazel is left with a jagged scar on her face.After Mum's death, Hazel, her other mother, Mama, and her little sister Peach needed a fresh start.So for the last two years, the Bly girls have lived all over the country.They travel from town to town, never settling anywhere for more than a few months or so.But when the family comes to the town of Rose Harbor, Maine, a small fog-draped beach town full of roses and rocks, Hazel senses a wildness to it that feels like magic. And when Mama runs into an old childhood friend Claire, suddenly Hazel's tight-knit world is infiltrated.To make it worse, she has a daughter Hazel's age, Lemon, who can't stop rambling on and on about the Rose Maid, a local myth a hundred and fifty years old about how a local girl was so heartbroken she turned into a mermaid. Soon, Hazel finds herself just as obsessed with the Rose Maid as Lemon is-because what if magic were real?What if grief really could change you so much, you weren't even yourself anymore?What if instead you emerged from the darkness stronger than before?