In a small lakeside village near Mount Fuji, mysterious occurrences spark fear among the residents when strange fossils are discovered deep within nearby caves. A visiting geologist, Kazuma, hoping to impress his childhood sweetheart Akiko, investigates these findings. His initial excitement about the scientific discovery quickly turns to horror as rumors intensify about a monstrous creature lurking in the lake. Residents recount tales of seeing gigantic prehistoric beasts during their fishing trips. Skeptical at first, Kazuma soon witnesses bizarre happenings firsthand. Meanwhile, Akiko is drawn into the mystery when vivid nightmares reveal clues about the creatures.

As tension mounts, an atmospheric shift signals the release of long-dormant dinosaurs and a terrifying pterosaur-like creature from their ancient slumber, causing chaos and destruction in the region. With the local authorities dismissing the claims as mere folklore or hallucinations, Kazuma and Akiko embark on a dangerous quest to uncover the truth and devise a plan to stop the chaos. They race against time, navigating through underground passages, battling skepticism, and confronting their own fears. As these creatures wreak havoc, their determination is tested by forces they don't fully understand, pushing them to the edge of survival.