一颗陨石撞击苏格兰偏远森林，意外唤醒了自尼安德特人时代就蛰伏地底、以骨骼为食的远古克苏鲁式怪兽 “守骨异兽”。1976 年，调查者詹姆斯・惠勒深入洞穴后离奇失踪，仅留下一张怪兽剪影的 8mm 胶片。数十年后，他的孙女奥利维亚为寻找同样失踪的母亲，带领一群好友与怪兽专家哈里斯教授，深入洞穴系统调查连环失踪案，却不知自己正被这只地底生物步步猎杀，陷入绝境求生的猎杀游戏。
当昔日的童年挚友离奇离世，一群老友重聚于她那座充满诡异回忆的豪宅，试图厘清过往。然而，悼念瞬间沦为绝境：她曾主持的经典儿童节目中，那些形象可爱的毛绒玩偶竟变成了嗜血的杀戮机器。
Nicole and Sebastian arrive to find the farm overrun by mysterious squatters who claim they can conjure spirits. As Sebastian attempts to violently run them out, Nicole is lured into their world, desperate to contact her dead daughter…forcing the couple to deal not only with the spirit world, but their own inner demons.
