The film centers on a duo of clumsy, heavyset police officers who become entangled in a drug smuggling investigation. Agent “J” (played by Zhang Wen) suffers a head injury during a high-stakes mission, which damages his hypothalamus. During his recovery, J gains significant weight, reaching three hundred pounds, and develops severe narcolepsy, yet he still sees himself as a top-notch agent. Eventually, J is assigned a new mission in Japan to retrieve sensitive documents. After securing the files, J impulsively opens them and decides to continue working undercover for the organization, but he collapses in an izakaya. Upon waking up in the hospital, J meets a security guard named Handsome Hao (played by Bei-Er Bao). Determined to prove his worth, Handsome Hao insists on joining the mission. Together, the unlikely partners face a series of absurd and perilous challenges as they carry out their assignment.