Late autumn, 2017. A solo climber disappears near Barker Pass, high in the Wyoming Rockies. Search and rescue finds her tent, her gear, and a journal with pages torn out. Luna's friend, a ranger named Nora, was one of the last people to speak to her. Now Nora can't stop thinking about what the woman said about the singing — a low hum that came from the ridge at night. Luna pieces together what happened through Nora's notes and her own visit to the pass, where she heard it too: a sound that isn't wind, isn't rock, and doesn't stop when you cover your ears. A story about the draw of high places, and the things that wait for us in the quiet.