Seo Do-cheol is a merciless police detective, who investigates the suicide of a truck driver named Bae, where he learns from Bae's son that Jo Tae-oh, the sadistic third-generation heir to powerful conglomerateSinjin Group has assaulted Bae as the latter protested against the conglomerate for back-payment. Do-cheol personally begins the investigation, which enrages Tae-oh. Later, Tae-oh uses his influence to make Do-cheol handle another case. He also tries to bribe Do-cheol's wife with the help of his conglomerate's SVP Choi Dae-woong, but she refuses, where Do-cheol threatens Tae-oh after learning this.
Do-cheol takes the help from a reporter to publish the news, but to no avail. Tae-oh hires a logistics contractor named Jeon to finish Do-cheol and also makes the Internal affairs to interrogate him, but is timely saved by his team leader Oh. Do-cheol escapes from a murder attempt by Jeon, where a detective gets stabbed. Using the opportunity, Do-cheol and his team discover evidences and gets approval for the investigation against Tae-oh, but Tae-oh's father and the conglomerate chairman Jo makes Dae-woong to take the blame. With his team's help, Do-cheol learns that Bae was killed after he tried to seek revenge for assaulting him, and was made it as a suicide.
After inquiring Dae-woong, Do-cheol learns that Tae-oh is planning to escape to Singapore. Before leaving, Tae-oh throws a party where he meets his former girlfriend Jeong Da-hye (who is pregnant with his child) and tries to kill her when she abuses him. Do-cheol forms a plan where they plant a false case against Tae-oh for assaulting his girlfriend, and the cops fight with the bodyguards to arrest him. After an intense car chase, Do-cheol and Tae-oh engage in a hand-to-hand combat where despite brutal injuries, Do-cheol manages to arrest Tae-oh, who is later produced for a trial at the Supreme Court along with Dae-woong, and are sentenced to prison. In the hospital, Do-cheol recovers from his injuries and soon returns back to duty.
Ryoo Seung-wan and production company Filmmaker R&K confirmed that they agreed to make a sequel, which was supposed to hit theaters within two to three years of announcement.[26][27][28] It was reported that Hwang Jung-min and Oh Dal-su will reprise their roles, and actor Jung Hae-in is also being considered to succeed Yoo Ah-in as the antagonist.[29] It began filming as Veteran 2 in December 2022 with the cast of Hwang Jung-min, Oh Dal-su, Jang Yoon-ju, Oh Dae-hwan, and Kim Si-hoo.[30] Titled I, the Executioner, it premiered as a midnight screening at the 2024 Cannes Film Festival.[31]
Remake
A Chinese remake starring Sun Honglei was scheduled for release in China in 2017.[32] Eventually, the remake The Big Shot was released in 2019 and starred Wang Qianyuan.[33]