Minnesota, 1977. For the teens of one close-knit community, summer means late-night swimming parties at the quarry, the county fair, and venturing into the tunnels beneath the city. But for two best friends, it's not all fun and games. Heather and Brenda have a secret. Something they saw in the dark. Something they can't forget. They've decided to never tell a soul. But their vow is tested when their friend disappears--the second girl to vanish in a week. And yet the authorities are reluctant to investigate. Heather is terrified that the missing girls are connected to what she and Brenda stumbled upon that night. Desperately searching for answers on her own, she learns that no one in her community is who they seem to be. Not the police, not the boys she met at the quarry, not even her parents. But she can't stop digging because she knows those girls are in danger. She also knows she's next.