The four Ryudo brothers hold an ancient and powerful secret. As humans they possess supernatural speed and strength, but in moments of mortal danger, they become the terrifying, unstoppable dragons of legend.

The soulless researchers of the Mulligan Foundation believe that the Ryudo brothers are unusually powerful men - completely unaware of their true nature. They hope, that with the proper persuasion, the brothers will cooperate and agree to become agents of the Foundation - as assassins and saboteurs.

To accomplish this, the Foundations top agent, Lady L, has kidnapped one of the youngest brothers. He is caged like an animal, and carried to Yokota Air Force base.

Meanwhile, the remaining Ryudo brothers are racing to rescue him because they know that if he is pushed beyond his limit, the dragon within him will awaken and become an unimaginably destructive monster! Will his brothers be able save him in time