An ex-special agent CHA Tae-shik's (Won Bin) only connection to the world is a little girl, So-mi (Kim Sae-Ron), who lives next door. Her mother, Hyo-jeong, smuggles drugs from a drug trafficking organization and entrusts Tae-shik with the product, without letting him know. The traffickers eventually find out about her smuggling and kidnap both Hyo-jeong and So-mi. Tae-shik is now drawn back into the world in a frantic search for So-mi's whereabouts...