Monsters really do exist.
It's the late 1970's and almost 17 year old Shelby McDonald is looking forward to summer vacation. A trip west leads himself and his parents to Banff, Alberta in the heart of the Rockies.
Here, he meets and attractive girl by the name of Debbie Foster and the two make plans to meet after a day trip to the park's attraction the Hot Springs Cave. Inside the odorous tunnel and cave, Shelby finds there's something far worse than claustrophobia stalking him. A creature that has lived in the sulfur springs for generations. Saved from a chance encounter by Dallas Durning, a malacologist sent to study the Banff Springs Snail, he learns that Dallas has been studying these creatures as well. They're harmless, he tells the frightened teen.
But he's wrong. Dead wrong.
The three, now thrust together out of need, find themselves locked in an adventure that would lead them back into the cave and into the very heart of the monster's lair and wrath.