A heroin deal is set to occur at a nightclub. Undercover police are also in the nightclub waiting to make their move. A nightclub employee takes the heroin into the locker room. While the nightclub employee changes out of his uniform he is tazered from behind. Hyo-Jeong (Kim Hyo-Seo), a dancer at the nightclub, walks off with the heroin.

Cha Tae-Sik (Won Bin), known only as "ajusshi" in his neighborhood, runs a dilapidated pawn shop in a seedy part of town. He associates little with those around him except a young girl named So-Mi (Kim Sae-Ron). So-Mi lives near Cha Tae-Sik's pawn shop and often comes over when her junkie mother Hyo-Jeong has men over. One day, So-Mi's mother Hyo-Jeong comes into the pawn shop. She pawns off to Cha Tae-Sik a bag with a camera, which he will hold until she pays him back. Cha Tae-Sik is unaware that in the bag is the heroin she stole from the nightclub.

In a few days vicious mafia men come looking for So-Mi's mother knowing she stole the drugs. In the process they break into Cha Tae-Sik's pawn shop and holds him up. He hears on a cellphone young So-Mi's screaming voice and then gives the gangsters the bag that was brought to him by So-Mi's mother. The gangsters leave the pawn shop, but before they leave they shoot one of their own men dead. The gangsters also drive off with So-Mi and her mother.

Cha Tae-Sik must now go after the dangerous mobsters who stole So-Mi. In the process, Cha Tae-Sik must also face off against the police and his own mysterious past …