Fanny Fitzpatrick is back again, with a whole new set of mythic problems that could ruin her friendships with Athena and Gemma. It's the end of the school year. For most kids, it's time to relax and get ready for summer. For Fanny, there's work. She has a brand-new baby brother, and she's been hired by Zeus to look after his "injured" son. And she still has her and her friends' cheesemaking business! Fanny is overwhelmed. But then she meets three sirens who want Fanny to join them on Feather Island for a summer of singing, instrument playing, and fun at the beach. The program is totally free and could start an amazing musical career-the thing that Fanny has always wanted the most. Athena and Gemma are dead set against it. Athena says that the sirens are bad news; that their whole purpose in life is to lure men to their deaths with their beautiful singing. Gemma says that Feather Island is part of a network of unmappable islands, the type of place where criminals and sketchy organizations hoard their wealth and do their crimes. Surely, the sirens don't do that anymore, right? All that stuff was a long time ago. If the sirens want to keep their island paradise a secret, well, that's not so weird, is it? Fanny has talked to them, and she just knows that they aren't as evil as everyone says. They are perfectly nice ladies. Right? Follow Fanny Fitzpatrick as she navigates big sisterhood, friends who disapprove of her life choices, burning ambitions, and a bunch of sirens luring her away to their private island.