Girl at the bottom of the sea

"Sophie Swankowski is the hero from the stories she's been hearing all her life: she's the girl who will save the world. Or so she's been told. Now she and her unlikely guardian--the gruff, filthy mermaid Syrena--must travel the pitch-black seas from broken-down Chelsea, Massachusetts, to Syrena's homeland in Poland. Along the way, Syrena will reveal the terrible truth about her past, and teach Sophie about the ages-old source of her newly discovered power. But left behind in Chelsea, without Sophie to protect them from the dark magic she's awakened, what will become of Sophie's friends and family?"@en
""Sophie Swankowski is the hero from the stories she's been hearing all her life: she's the girl who will save the world. Or so she's been told. Now she and her unlikely guardian, the gruff, filthy mermaid Syrena, must travel the pitch-black seas from broken-down Chelsea, Massachusetts, to Syrena's homeland in Poland. Along the way, Syrena will reveal the terrible truth about her past, and teach Sophie about the ages-old source of her newly-discovered power. But left behind in Chelsea, without Sophie to protect them from the dark magic she's awakened, what will become of Sophie's friends and family?"--Page 4 of cover."@en