Family is forever. Until now. Kenzie and Quinn aren’t just stepsisters? they’re best friends. They’re spending the summer with their grandmother, kayaking in the marshy coastal islands she calls home. The Outer Banks are also home to a herd of wild ponies, and the girls fall in love with a fragile newborn foal that they name Starling. But even blue skies and sandy beaches can’t distract from what’s going on back home. Things between their parents aren’t the way they used to be, and the constant fights have left Kenzie and Quinn anxious and confused. They can’t remember a time when they weren’t a family. If their parents divorce and Quinn and her mum move away, will they even still be sisters … or will they be nothing? As their world shifts around them, the girls swear to do the one thing they can: keep Starling safe.