In the last gasp weeks of 1957, nine-year-old pals Rand and Will patrol their sleepy California beach town investigating their greatest mystery yet: the Big Gyp. Like their heroes Frank and Joe Hardy, the boys sleuth out secrets hiding in plain sight. New, man-made objects arc across the night sky, replacing Santa and his sleigh – fathers and mothers seem on the verge of important, unspoken changes – and a haunted mansion pulls at them like a strong Pacific tide. Clues begin to piece together a darker truth hidden in Christmas and the promise of the New Year. Inevitably, their detective work sweeps them into an adult world spinning on another axis. And the boys find themselves confronting a holiday season among the dunes and winter fog more puzzling than any before. The mystery they solve will change their friendship – and possibly end it.