Lila Willow has always moved through the world quietly — not teased, not lonely exactly, just overlooked, like a bookmark someone forgot to pull out. Every afternoon she walks the towpath along the Erie Canal in Lockport, telling the water the things no one else stops to hear.

On her twelfth birthday, her grandmother places an old brass lantern in her hands — carved with tiny stars and a promise every Willow girl has carried before her. That night, the ripples on the canal start behaving strangely. And the town’s oldest legend, the shy creature everyone calls the Canal Shark, turns out to be less legend than anyone imagined.