Duke Togo, aka Golgo 13, gets out of jail with assistance from the FBI and the CIA in Texas. Jake Quade, a gangster turned CIA informant, hijacked a domestic flight after killing a sky marshal and stealing his side arm with the threat of blowing it up with smuggled C-4 explosives. Golgo 13 snipes him in the aircraft's cockpit from a long distance from a nearby airfield after getting a highly modified .308 Winchester bolt action sniper rifle.

Golgo 13 is hired by a representative of the U.S. Securities and Exchange Commission when he was told to target a mafia financier in New York. Despite getting into trouble when his used .30-06 Springfield cartridge fell down from his apartment balcony due to the appearance of a stray cat, Togo tries to cover his tracks when a desperate detective of the NYPD starts to hound him over his stay in New York City.

What began as a simple mission to stir up trouble for racers driving Japanese-made vehicles in a rally race turns into a match of sniping when Golgo 13 is targeted by the Savine brothers, ex-French Foreign Legion soldiers turned mercenaries armed with modified XM29 OICW and FN F2000 bullup assault rifles while being aided by customized digital scopes made by a European arms dealer named Kaizer in order to market them to numerous military forces from around the globe.

Linda, the wife of a mafia leader in New York City hires Golgo 13 for the purpose of assassinating him so as to start another life all over again in Florida. Things gets complicated when the mafia boss kills one of his henchmen after being accused of trying to be in an affair with Linda, resulting in a small gang war fight before Golgo 13 was able to get rid of his targets and unfortunately Linda when she decides to kill him.

Bob Stigner, vice-president of Conan Associates, hires an ex-Polish olympic athlete and soldier named Ledell Nikolavitch to assassinate the company's president and current leader Ted Conan in order to take over the entire company despite what Ted had done to help Bob escape from his past problems. However, Ted is wise to Bob's game and decides to hire Golgo 13 to assassinate both Bob and Ledell for good.

Golgo 13 is hired out by a mobster to go to Massachusetts and assassinate an anti-crime analyst during the state's presidential elections. When Golgo 13 is arrested by FBI agents for assaulting an agent, he is grilled regarding the murder and the PPS-made revolver that he used until a lawyer named Mr. Barton begins to question the loopholes in the FBI's accusations against Duke.

Golgo 13 is hired by Simpson a famed violinist from London Symphony Orchestra to sabotage a charity concert lead by his replacement Kaspersky by shooting the G-string from his violin.

Golgo 13 is hired by a mafia boss to kill another heavy-handed mafia boss. The targeted boss learns of Golgo's attempt and installs bulletproof glass and sends emissaries to analyze Golgo's handgun response time. Golgo 13 must now find a way to defeat the bulletproof glass and overcome research of his own abilities while avoiding three assassins sent to kill him.

Golgo 13 is arrested and sent to Pandora Island Prison, an isolated prison somewhere near the Alaska mainland to rescue a prisoner named Patrick Zalas despite being under the thumb of a sadistic and corrupt warden named Kickers. But after the two escape, Golgo executes him under orders of Patrick's bosses.

Golgo 13 assassinates a drug lord after he attacks and wipes out his FBI and NYPD escorts before heading to Hong Kong to do another job when he finds out that a lookalike was responsible for hiring him. After realizing that the lookalike was merely a gangster named Spike Jordan, Duke kills him with cyanide gas.

Golgo 13 is hired to assassinate the Jordanian emissary to the United States, while the emissary transfers from a plane to his helicopter. However, a young, hot-shot sniper is hired by the American State Department to take Golgo out before he accomplishes this. By leaving two disassembled rifles in fake sniping points, Duke is able to fool the inexperienced gunman. Golgo then uses an M-16 to take out both his new rival and the helicopter.

In Baltimore, Maryland, a rising American football star named Lionel Blue was assassinated by Golgo 13 by using his M-16 in a hidden rangefinger after being hired by a disgruntled football player via football gambler. An old-fashioned detective and the Baltimore police try to pin the evidence on him, the difference by the use of technology before Golgo 13 destroys the CSI Department's computer equipment with assistance from Flannagan despite being in a hospital under pretense of a potential cholera infection.

Victor Lance, a paparazzo photographer, decides to take a photo of Golgo 13 before he retires for good. Unfortunately, Golgo 13 takes out Lance's camera with the help of reflected sunlight on his camera before Golgo takes out his target in Britain.

The American government hires Golgo 13 to eliminate a Syndicate-established hideout where poisons from various animals are weaponized by the CIA. However, another assassin named AX-3 is also hired out to do the same thing Golgo was suppose to do. AX-3 is eventually killed when his handler informs him of his orders to eliminate Golgo 13.

Golgo 13 is hired by the New York Mafia to assassinate an international assassin. She turns out to be Eva Kruger, a woman Golgo had met on a cruise ship when an unknown terrorist had planted a bomb on it. The two parted ways after he defused it to save the passengers despite being told by the ship's crew to evacuate with the rest of the passengers. But even though Eva decides to retire as an assassin and be a civilian, Golgo had successfully assassinated her from a distance on another boat.

Fueled by the murder of his fiancée by the new underground cult the NYPD had been investigating, a NYPD Officer hires Golgo 13 to assassinate the cult's masked leader, Michael. However, the cult's members, fearless of death, go to any lengths to protect its leader, a self-proclaimed saint. As Golgo 13 infiltrated the cult, he is quickly recognized as a threat and ordered to be killed. Though, he thwarted their plans and escaped while being pursued by the cult's extremist followers.

On a routine assassination job in Hawaii, Golgo 13 spots an old FBI detective named Leon Goldman, who had tried to charge him with a previous assassination in San Francisco. At the scene of the current assassination, Goldman automatically knew that Golgo 13 was the sniper, but kept quiet because he did not wish to deal with such a trivial case any longer and tries to convince Golgo 13 to leave. At the end of episode Golgo 13 kills Leon himself.

Golgo 13 is hired by a MI5 operative, who had been able to infiltrate covertly the security detail of Louis Steinbeck III, an aristocratic man supposedly of French royal descent under orders from the British government. Golgo is hired to assassinate Steinbeck III as he is the leader of a secret rogue intelligence organization that sells out all types of classified information to various countries called MC-130. However, the MI5 operative/Steinbeck III bodyguard learns that Golgo did not target Steinbeck III but instead, went for the butler as he was the real leader of MC-130 when the hit was in operation.

Golgo is deployed on a covert mission in England to locate and kill a reclusive millionaire named Vargas Walton who has been "keeping" women as his guests in his estate located at an artificial island, ready to have healty organs from them to be harvested and kept ready for donors while using the funds from organ donations to finance several terrorist groups. The millionaire is protected by high-tech bulletproof glass, making an assassination attempt from the sea or air nearly impossible coupled with an ex-expert Olympic shooter named J.J. as the head of his bodyguard detail.

Golgo is sent to Malta on a secret mission on an assignment from the British government after a Foreign and Commonwealth Office employee named Arnold Glaston went rogue and was said to have sold national secrets to Russian companies, forcing him to escape overseas by marrying a girl named Stella in Malta. The mercenary follows Stella everyday to determine Arnold's location despite being told that he had escaped to America. Even with persistence from MI:6, Golgo was able to determine that Arnold had planned to return back to Malta, which enabled the assassin to complete his mission with success.

Golgo is hired by a man from the rural part of Brazil, seeking revenge on a man named Falcon a leader of the Garimpeiro and his minions for the death of his family and the Brazilian Military Police for letting it slide. He performs this task by hijacking a plane and asking three million in ransom to lure the Garimpiero and the police into chasing him by jumping down to the amazon.

A small family-run motel hears news of a casino robbery when Golgo turns up to stay. Hank, the son of the family returns home with another man having executed the robbery. The blind mother is suspicious of Hank and is unnerved by Golgo, but the assassin leaves before anything happens. Confronting Hank, the mother accidentally shoots Hank and the accomplice escapes to deliver the money to his boss, without realising that Golgo has been hired by the mob to kill those responsible for robbing their casino.

The plane that Golgo travels on has been hijacked by terrorists demanding money, who intend to escape with it before blowing it up. Looking at the passenger list, SIS decided to hire Golgo and gave him a message to him to take out the hijackers.

Brigitta, a female assassin is hired to kill Golgo 13 but she knows she is no match for him. As a means to even out the contest she meets with him and gives him the job of taking out a mafia boss who is using a meat factory as a front. Whilst Duke is preparing for the job she informs the boss of Golgo 13 who promptly sends over his band of goons to kill him. However he escapes and leads the goons straight to the meat factory and lures them out of their cars where the sirocco wind is blowing the sand from the desert restricting their visibility, where he picks them off. Brigitta planned this as a way to put Duke at a disadvantage so that his eyesight would be impaired when it came to the duel. Donning a pair of goggles she sets out to finish off Golgo but she underestimates just how well-prepared he is.

The aide to the US minister of foreign affairs hires Golgo to kill Jose Campos, an immigrant drug distributor who is in custody but is still organizing the smuggling of drugs into Florida. Meanwhile a new type of armored van is stolen and used in springing Campos from a prison bus. In order for the US to save face and with the authorities unable to stop the armored van, the aide requires that Golgo completes the job before Campos makes it to Mexico. Duke acquires the schematics to the van and a specialized gun with armor piercing bullets and masquerades as a SWAT team member at a roadblock and successfully shoots Campos through the van's weak point.