A shady drug dealer named Addictem tries to sell his dangerous drug product called Crystal Twyst to the streets of Empire City. He even tries to join up with Big Boss and his crooks to help promote the drug product. But Big Boss rejects his offer. For once, there is a spark of morality inside this otherwise corrupt fat man. He even orders his crooks to reject Addictem's product completely. Easier said than done. For unfortunately, while out on a heist, Berserko accidentally falls into a crate full of Addictem's Crystal Twyst, which cause him to become unconscious and be taken to the hospital. As a result, Big Boss and his Crooks... of all things... join forces with COPS in a successful effort to take down Addictem and end his drug selling business for good.