The police are staking out Park Joon-gil for the murder of Hwang Choong-nam, and jaded detective Jung Jae-gon is being pressured to close the case, particularly by his former superior Moon Ki-beom, who lost his badge for corruption. Joon-gil was once the mob enforcer for Jay Investment, but had fallen out of favor when he embezzled and stole the heart of Kim Hye-kyung, the girlfriend of the company's vice president Park Jong-ho. Jay Investment representative Min Young-ki approaches Jae-gon and offers him US$5,000 to ensure that Joon-gil is maimed during the arrest as payback. Jae-gon reluctantly agrees, but a botched arrest sends Joon-gil on the run, and Jae-gon decides the best way to find him again is by sticking with Hye-kyung, hoping she will lead him to the fugitive. Hye-kyung now works as a bar hostess to pay off her substantial debt to Jong-ho, and Jae-gon threatens his way into an undercover job as a floor manager at the nightclub she works at. Introducing himself as Joon-gil's former cellmate Lee Young-joon, Jae-gon begins to spend time with the suspicious Hye-kyung and gradually wins her trust. But when Joon-gil returns asking Hye-kyung for money for a potential deal, Jae-gon's newfound feelings of love and jealousy rise to the surface.
This is the second film Oh Seung-uk has directed, 15 years after his directorial debut Kilimanjaro (2000).[6] Oh was a prominent screenwriter in the 1990s, having written Green Fish (1997) and Christmas in August (1998).[18][19][20]
Lee Jung-jae was originally cast in the leading role as Jung Jae-gon, but dropped out after he was injured on the set of his 2014 film Big Match. He was replaced by Kim Nam-gil.[21]
The Shameless was released on May 27, 2015. It opened at fourth place in the box office, grossing ₩2.14 billion (US$1.92 million) from 272,000 admissions in its first five days.[23][24] By the end of its run, it had grossed ₩3,255,796,431 (US$2,805,292) from 413,836 admissions.