In the suspenseful ambiance of Minnesota, 1977, a group of teenagers revel in the freedom of summer, diving into the depths of a local quarry and wandering in the hidden tunnels lurking beneath their city. Heather and Brenda, however, are plunged into a chilling adventure when a casual exploration leads to a harrowing discovery. Confronted with a truth too grim to share, they resolve to seal it away in silence. This oath is put to the ultimate test as girls begin to disappear, an alarming pattern that goes unnoticed by the town's authorities. With a vanished friend and a tightening noose of secrecy, Heather finds herself entrapped in a web of deception spun by those she trusted most. As she embarks on a solitary quest for the truth, she's swept into a perilous search, piecing together a puzzle where every revelation draws her closer to an unseen predator--a predator that has now marked her as its next target.