On a frozen November night in 1997, Luna's father took a shortcut across White Rock Bridge—a rusted iron span over a dry creek bed outside of Bellflower, Illinois. He came home pale, smelling of river mud, and refused to speak about what he'd seen. Twenty-seven years later, Luna drives the same road at the same hour, determined to understand the low, two-note whistling that has haunted her family's sleep for three generations. What she finds under the bridge is not a ghost, not a memory—but something that has been waiting, patient and hungry, for someone to finally answer.