Dr. Jonathan Hemlock, professor of art and expert mountaineer, is a long retired government assassin called upon to return to work for two more sanctions, or assassinations. He has used the small fortune he made from previous sanctions to amass a small but impressive art collection, primarily made up of stolen pieces smuggled into the U.S. from Europe.
His boss is "Dragon", an albinistic ex-Nazi confined to semi-darkness and kept alive by blood transfusions. Dragon wants Hemlock to sanction two men responsible for the death of another government agent, a man who was also a friend of Hemlock's. But Hemlock refuses, insisting he is retired and uninterested in the work, regardless of the personal turn it has taken. Dragon will not be denied, however, and he says the IRS might be curious to know how he acquired his art collection with his professor's salary, in effect hinting that he will frame Hemlock for tax evasion. He is informed that the target is a member of an international climbing team about to ascend the north face of the Eiger in Switzerland, a treacherous route which has claimed many lives.
Hemlock goes to train in Arizona with his friend, Ben Bowman, then both proceed to Switzerland to join the climbing team. There is, of course, much conflict within the team, mainly due to clashing egos. The expedition eventually sets out, but encounters extremely bad conditions. Eventually rescued from the railroad that runs through the mountain, Hemlock finds the target of his mission, but it is not the one he had expected.