The Comedians

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A ship arrives in Port-au-Prince, Haiti. Four of the alighting passengers are: Major H. O. Jones (Alec Guinness), a British businessman with a letter of invitation to do business with the government; Mr. and Mrs. Smith (Paul Ford and Lillian Gish), an elderly American couple who wish to set up a vegetarian complex for education and nutrition for the locals; and the central character, a cynical, washed-up hotel owner named Brown, portrayed by Richard Burton.
Upon arrival, Major Jones presents his credentials to Captain Concasseur (Raymond St. Jacques), a law enforcement officer, who notices that the official who invited Jones has been deposed and imprisoned. Concasseur and his men rough up and imprison Jones.
Brown has been bequeathed a hotel in the capital from his late British mother, but has been unable to sell it in his trip to New York City. Brown also has an ongoing affair with Martha (Elizabeth Taylor), the German-born wife of the Uruguayan ambassador to Haiti, Pineda (Peter Ustinov). When Martha and Brown have an argument, Brown goes to Mere Catherine's brothel where he discovers that not only has Jones been released, but he's a guest of Captain Concasseur and is enjoying the hospitality of Brown's favourite prostitute, Marie Therese (Cicely Tyson).
Jones has gained the favour of the new regime, who are keen to receive a supply of arms. They have paid a down payment, and Jones claims the weapons are impounded in a warehouse in Miami, but the weapons may be imaginary and a confidence trick by Jones. The government will not allow Jones to leave the island until they are sure the weapons exist.
Mr. Smith, a former "Vegetarian Party" candidate for the Presidency of the United States against Harry S. Truman, is given a tour of the new capital, an empty shambles called Duvalierville. He and Mrs. Smith follow a local procession that they believe is a religious ceremony but turns out to be an audience for executions by firing squad. Captain Concasseur and his men enter Brown's hotel and beat him up until Mrs. Smith bluffs the thugs by threatening to inform her husband, the American "presidential candidate." The Smiths depart the next day.
Brown watches as the Duvalier regime seeks to put down any dissent with an iron fist. He becomes friends with Dr. Magiot (James Earl Jones), the rebel leader.
As Brown becomes a reluctant participant in the planned insurrection, the rebels recruit Major Jones to provide military leadership. Jones has been regaling the other expatriates with his tales of heroism as a commando officer in the Burma Campaign that Brown does not quite believe. Brown hosts a meeting of the group, including Magiot, Jones, and Ambassador Pineda. But trouble ensues soon thereafterÂ â Duvalierâs spies from the Tonton Macoute are watching Brownâs Hotel Trianon and his every step.
The day after the meeting, three assassins confront Magiot while heâs performing surgery and cut his throat with a scalpel knife. Brown reluctantly agrees to drive Jones, who escapes by dressing as Brown's female cook, wearing drag and blackface. Taking him to a rebel base, Brown suspects that Jones has become involved with Martha Pineda. The inebriated Jones makes matters worse by bragging about his conquest.
Driving carelessly up the treacherous, winding road, Brown hits an embankment and breaks the carâs front axle. On foot, they arrive at a remote cemetery, the designated meeting point. They settle in for the night with Jones admitting that his jungle war stories were total fabrication, as was his claimed conquest of Martha. His wartime career involved running a cinema in India, and he'd never been with a woman he hadn't paid "or promised to pay."
In the morning, Captain Concasseur and one Tonton Macoute accost Brown at the cemetery. Brown denies that the Major is there, talking loudly to warn Jones. But a sleepy Jones approaches anyway. Commanded to stop, Jones turns and runs, but is killed. Brown is ordered into a jeep, but shots from rebels ring out. Concasseur and his henchman drop dead.
Asked about Jones, Brown tells the two rebels in dismay: "You arrived two minutes too late." The rebels plead with Brown to assume the role of Jones, seeing this as the only hope they have left. Brown hesitates, but relents after being asked whether he wants to continue living like this.
The three meet up with a ragtag group of poorly equipped rebels who believe that Brown is Jones. He gives a cynical, taunting speech, apparently without being understood, since the rebels speak French and he English.
The Pinedas are leaving the island. Petit Pierre (Roscoe Lee Browne), a journalist friend of Brown, tells them about a battle between government troops and rebels. He says two rebels have been killed, one "unidentified." As the plane takes off, Martha notices smoke on a hillside of the island. The question whether Brown has survived remains unanswered.

Question: Who is Brown having an affair with?
Answer: Martha.