In Nanga City, an island nation in the Pacific Ocean, prisoner Wuchuan escapes from prison after a monster attack on the city. Upon regaining his freedom, he discovers that the entire city has become a hunting ground for prehistoric monsters. To rescue his mother trapped in a chemical plant, he embarks on a perilous journey, during which his conscience awakens, and he ultimately leads everyone to defeat the prehistoric overlord, the Pangu King Serpent, and avert the city's disaster.