In an isolated island in Indonesia, an expedition is apparently seeking the legendary Yamashita's Gold. Out of the blue, they are attacked and seek refugee in an abandoned Japanese bunker. Soon they discover that the place was a secret laboratory in the World War II where the prisoners were guinea pig in weird experiments. Further, they are trapped inside with strong and resistant creatures created by these experiments. Will they succeed to escape from the dead mine?

When Nick Davis leaves prison after one year in solitaire, he is hired to operate forklift in a warehouse in the harbor owned by the Japanese Yakuza patriarch Isshin Tendo. The place is assaulted by the Italian Mafia leaded by Dino Campanela and Nick rescues and saves the life of Shuji Sawamoto, who is the representative of Yakuza interests in America. Shuji hires Nick to work for Yakuza and becomes his godfather in the family after his oath to join Yakuza. However, Nick is a lonely FBI undercover agent assigned to penetrate in the criminal organization. When the FBI discovers that Campanela is organizing a massive attack to destroy the Yakuza, Nick's boss Littman calls off the operation to leave the dirty work to the Italian Mafia. But the connection of Nick with Shuji and his goddaughter Yuko forces him to help his Japanese family.