Chad and Yard are two hit-men who are equally skilled at their jobs. They work under the supervision of Tran, the right-hand man of Madame Louie, the leader of an underground drug dealing business in Thailand. This makes Chad and Yard compete against one another to become number one. They are constantly competing and fighting against each other over every matter. Tran then sent the two on a mission to deliver Kookitno drugs, a new type of drug, to a client. Therefore, the two must be careful not to get followed or caught by the police, especially Police Colonel Cherdsak Chaya, who is heavily driven by his job as a narcotic police. Kookitno drugs are unique in that they produce faster side effects. Once ingested, one will quickly fall asleep and begin to hallucinate severely. In addition, when combined with the stimulant of music, the drug's effect will increase even more. If ingested beyond the recommended dose, it will drive a person mad to the point of killing others, committing suicide, and overdosing from the drug's toxicity.
While on duty to deliver the drugs, Chad was secretly ambushed, which resulted in him falling off the cliff. Police Colonel Cherdsak sent Police Lieutenant Sakchai, an undercover spy for the police, to disguise himself as Chad because he looks similar to Chad. He underwent surgery to look exactly like Chad even if Sak-Chai didn't quite agree with the method. This was a top secret case.
Meanwhile, drug dealers from Hong Kong and Cuba want to hire Yard to steal Kookitno's secret drug formula. Yard accepted the offer because they were willing to pay him a very high price for the job. Even though the deal was made top secret, it was unable to escape the ears of the DEA (Drug Enforcement Administration). Yard then met Rasamee, a tourist guide. He fell in love with her and asked her to take him and the drug dealers on a tour in Chiang Mai not knowing that she's actually an undercover cop.
When Lieutenant Sakchai awoken from surgery, they were ready to make the switch. The police had gathered every bit of information about Chad from his past history and personality traits to ensure they impersonate Chad accurately. When Sakchai woke up to see his face, he was so unhappy that he ran away and bumped into Tran. Tran then brought him to rest at the mansion because he thought he was Chad. He called Becky, Chad's lover to come take care of him. Becky knew that this Chad wasn't the same Chad, but she didn't say anything.
Furthermore, Pailu is a famous Chinese singer from Hong Kong. She is also an undercover cop who is working for China to bring down the criminals behind the Kookitno drug trade. All three undercover cops will some how cross paths and work together to bring Madam's Louie drug trade to an end.