Grim

Katie, Steve, Trish, and Sarah gather in Katie's home in Woodland Hills for a late-night spirit board session. As the planchette moves, Katie begins to convulse and speak in a voice not her own, signaling the Grim's presence. The encounter ends with a chilling realization that a dark force has been unleashed from the town's caves.

The Grim forcibly takes control of Katie, compelling her to verbally grant its freedom. The possession marks the creature's release from imprisonment and sets its plan into motion. Rob, Steve, and the others sense something has changed beneath the town.

With Katie under its control, the Grim slips into the cave systems beneath Woodland Hills. It begins to move freely, triggering a trail of sinkholes above ground. Animals fall prey first, and soon a woman named Mary is kidnapped.

The sudden sinkholes and tremors cause panic in Woodland Hills. The townspeople assume a mining company is expanding its tunnels, but Katie and Steve realize it is connected to the previous night's events.

An official named Rob, familiar with the town's tunnels, is dispatched to investigate. He begins organizing a plan to explore underground and locate the source of the disturbances.

Rob forms an impromptu spelunking team including Penny, Steve, Katie, Trish, Ken, Sarah, and Wendy, and they prepare to enter the cave system to search for clues and for Mary.

Within the darkness of the tunnels, the Grim ambushes and slaughters Trish. The team reels from the sudden loss as panic spreads among them.

While the group searches for Trish, the Grim kills Steve and abducts Ken and Sarah, taking them back to its lair where Mary is kept captive.

The group devises a plan to kill the Grim using dynamite. The attempt fails, leaving them to regroup and rethink their strategy while the Grim's power grows stronger underground.

Rob and the others manage to rescue the captives but are forced to leave Wendy behind due to her insanity and the Grim possessing her. The team grieves, knowing the danger is far from over.

With Ken dead, only Katie, Rob, and Penny remain to confront the Grim in the tunnels. The trio steels themselves for a dangerous confrontation with the otherworldly force.

They locate the place where the Grim was imprisoned and learn that bright light can imprison it again. They detain the Grim with flashlights, but as the sun rises, the Grim grabs Katie, sealing them both in a radiant prison.

Rob and Penny escape the tunnels, traumatized by the ordeal. Mary remains missing in the Grim's lair, suggesting she may still be under its control or hidden away beneath the town.