On August 22, 1962, the militant underground group OAS, angered by the French government’s decision to grant independence to Algeria, makes a daring attempt to assassinate President Charles de Gaulle. The assassination fails spectacularly, leaving de Gaulle and his entire entourage unscathed. In the following months, the OAS leader Jean Bastien-Thiry and several accomplices are soon captured, resulting in Bastien-Thiry’s execution.
The surviving OAS leaders, now hiding out in Austria, begin plotting another assassination attempt. They hire a skilled British assassin, known only by his codename "Jackal", for a whopping $500,000. The Jackal travels to Genoa, where he commissions a custom-made rifle from a gunsmith and forges a new identity with the help of a forger. In a brutal twist, he kills the forger when the man tries to blackmail him. The Jackal finds a way into the heart of Paris by duplicating a key to an apartment that overlooks the Place du 18 juin 1940.
Meanwhile, the OAS relocate to Rome, but the French Action Service takes a decisive step by kidnapping the OAS chief clerk, Viktor Wolenski. Though he dies during harsh interrogation, Wolenski divulges crucial information about the planned assassination, revealing the name "Jackal." In response, the Interior Minister convenes an urgent meeting with top French security officials. Police Commissioner Berthier recommends his capable deputy, Claude Lebel, to spearhead the investigation. While Lebel is granted special emergency powers, complications arise due to de Gaulle’s steadfast commitment to his public schedule.
In a careless moment, Colonel St. Clair, a personal military aide and cabinet member, unintentionally shares sensitive government details with his mistress, Denise—who happens to be an OAS operative. This leak ends up aiding the Jackal’s sinister plans. As the investigation deepens, Lebel suspects a British individual named Charles Harold Calthrop, who goes by the alias Paul Oliver Duggan, may have entered France.
Despite learning that authorities are onto him, the Jackal persists with his deadly mission. At a hotel, he encounters and charms the aristocratic Colette de Montpellier. However, after receiving a warning, he narrowly escapes just before Lebel and his team arrive. Following a near-fatal car accident, the Jackal steals a vehicle and takes refuge at Madame de Montpellier's estate. When he realizes that the police have already contacted her, he kills her to eliminate any potential leads. Adopting the identity of a bespectacled Danish schoolteacher named Per Lundquist, the Jackal discards Duggan's belongings into a river and boards a train for Paris.
As the body of Madame de Montpellier surfaces and her vehicle is recovered, Lebel shifts to a public manhunt without secrecy constraints. While at a Turkish bathhouse, the Jackal picks up a man, only to murder him later when the man recognizes him from a news broadcast identifying "Lundquist" as a murder suspect.
In a meeting regarding the assassination plot, Lebel articulates his belief that the Jackal intends to shoot de Gaulle during the upcoming Liberation Day ceremony, set to commemorate the liberation of Paris in World War II. Disclosure unfolds as Lebel plays a recording that implicates Denise in feeding information to the OAS. St. Clair hastily excuses himself but is soon found having taken his own life. Due to the loss of the initial suspect, the Interior Minister reinstates Lebel to continue the investigation.
On Liberation Day, the Jackal disguises himself as an elderly amputee, gaining entry into a building using the key he procured earlier. In an apartment overlooking the celebration, he meticulously assembles the rifle concealed within his crutch. Just as the ceremony begins and de Gaulle prepares to award medals, Lebel discovers the security breach. While the Jackal aims his weapon, he narrowly misses de Gaulle when the president leans forward unexpectedly. As he attempts to fire again, Lebel and a policeman rush in. In the ensuing chaos, the Jackal shoots the officer but is ultimately shot and killed by Lebel.
Upon returning to England, police search for answers regarding Charles Harold Calthrop, the unsuspecting man whose identity was exploited by the Jackal. When the real Calthrop appears at Scotland Yard, he is cleared of all suspicion, leaving authorities baffled and searching for the true identity of the assassin, whose remains are interred in an unmarked grave, with only Lebel bearing witness to the fallout of this failed assassination plot.
