Art professor and mountaineer Jonathan Hemlock (Clint Eastwood) is a retired government assassin called on to return to work for two more "sanctions", a euphemism for officially approved killings. During his career with a secret government agency called "C2", Hemlock amassed a private collection of 21 rare masterpiece paintings, paid for from his previous sanctions. The director of C2, Dragon (Thayer David), is an albino ex-Nazi confined to semi-darkness and kept alive by blood transfusions. Dragon wants Hemlock to kill two men responsible for the death of another government agent, code name Wormwood. Insisting he is retired, Hemlock refuses until Dragon threatens to expose Hemlock's art collection to the IRS. Hemlock agrees, and travels to Zurich, where he carries out the first sanction for $20,000, twice his usual fee, and a letter guaranteeing no trouble from the IRS.Returning from Europe, Hemlock meets C2 courier Jemima Brown (Vonetta McGee), who seduces him and steals his money and IRS exemption letter. Dragon agrees to return them if Hemlock completes the second sanction. Hemlock is reluctant, but agrees when he learns that the C2 agent killed, Wormwood, was in fact his old friend Henri Baq. Dragon agrees to pay him $100,000 plus expenses, and tells him the target is a member of an international mountain climbing team that will attempt an ascent of the north face of the Eiger mountain in Switzerland. Hemlock will be the American member of the team, and must kill one of the climbersâDragon is unsure of the target's identity, but confirms that the man walks with a limp.Hemlock travels to Arizona to train at a climbing school run by a friend, Ben Bowman (George Kennedy), who whips him back into shape with the help of an attractive Native American woman named George (later revealed to be Bowman's daughter). Hemlock also encounters an enemy, Miles Mellough (Jack Cassidy), a former ally from the military who betrayed him in Southeast Asia. Mellough tries to kill Hemlock by hiring George to drug him, but Hemlock survives. Later he lures Mellough and his bodyguard into the desert, where he shoots the bodyguard and leaves Mellough to die in the sun.Hemlock travels to Switzerland with Bowman, the "ground man" or supervisor of the climb, and meets the other members of the climbing party at the Hotel Bellevue des Alpes at Kleine Scheidegg. The headstrong and condescending German member, Karl Freytag (Reiner SchÃ¶ne), presents his proposed route up the mountain, and the team agrees that he will lead the party. The following morning, the men begin their ascent of the Eiger north face, and soon the weather conditions become poor. The French climber is struck by falling rocks and later dies. With Hemlock now leading, the surviving members retreat towards a tunnel window that connects to a railroad station inside the mountain, carrying the dead climber between them. At the last moment, Freytag and the Austrian, Anderl Meyer (Michael Grimm), fall to their deaths. Hemlock is saved, dangling alone a few meters from the tunnel window.Bowman and a rescue crew make their way through the Eiger to the tunnel window, where they attempt to throw a rope to Hemlock. Hemlock notices Bowman is limping, a sign that identifies him as Hemlock's target. Hemlock says, "You're limping, Ben," reluctant to trust that Bowman will rescue him. Bowman throws him the rope, and Hemlock attaches it, then reluctantly cuts his own rope. He falls onto Bowman's rope, and is pulled into the tunnel to safety. On the train back to Kleine Scheidegg, Bowman admits he became involved with "the other side" years earlier and had no idea there would be a killing. Bowman admits he had become involved with Miles Mellough to whom he was indebted for getting his daughter George off drugs.Back at Kleine Scheidegg, Bowman approaches Hemlock, looking to mend his relationship with the assassin. Hemlock tells him that C2 believes the target died on the mountain, and that there's no reason to tell them otherwise. After Bowman leaves, Jemima Brown joins Hemlock, who takes a phone call from Dragon, who is convinced that Hemlock killed all three of the other climbers intentionally to ensure he killed the target. Jemima wonders if Dragon is correct.
Output: Question: Who double crosses Dr. Jonathan Hemlock?, Answer: Ben Bowman