In the heart of South Korea, a wedding celebration is rudely interrupted by news of a devastating earthquake. The chaos reveals a colossal, ancient reptilian monster named Yongary, emerging from the depths and wreaking havoc across the countryside. Geologists and military forces struggle to understand and counter this immense threat. Amidst the turmoil, a young scientist named Il-woo, armed with his expertise and determination, teams up with his astronaut friend to stop the monstrous rampage. However, their initial efforts prove futile as the monster demonstrates its supreme power.

While scientists scramble to devise a plan to neutralize the beast, Yongary moves from the rural landscape into the cityscape, causing widespread destruction and panic among the residents. As fear grips the nation, Il-woo and his companions discover a potential clue linked to Yongary's weaknesses. This revelation propels them on a desperate mission, racing against time to develop a solution that could save humanity from imminent annihilation. Amidst growing desperation, they venture to put their theory to the test, encountering both thrilling and dangerous obstacles along the way.