An Evil Immortal, Kuyler, has hired himself out down through time as an assassin — the most successful killer in all of history. He strikes again in modern day Paris using his signature disguise as a mime. A French Police Detective, LeBrun, suspects that Duncan MacLeod is connected to Kuyler, but of course he cannot imagine that Kuyler once killed an eighteenth-century baron under MacLeod's protection. When LeBrun is wounded protecting Tessa from Kuyler's men, MacLeod confronts the Immortal assassin and puts an end to his centuries-old reign of terror.

Warning comes from MacLeod's old friend Darius, a monk over 2000 years old, that Grayson, Darius' one-time protege, is now stalking Darius' other students — among them, possibly, MacLeod. Grayson, disillusioned that his former comrade-in-arms has become a man of peace, is killing Darius' mortal students in order to draw the monk off holy ground and into combat. MacLeod must protect peace activist Victor Paulus, another of Darius' students, from Grayson's plot to assassinate him. Later he joins Richie and Tessa in France where they will live while Tessa takes up her new job as curator of a traveling collection.

Tessa witnesses the murder of a painter, Anne Wheeler, but the absence of a body leads everyone but MacLeod to doubt her story. MacLeod supports Tessa in her quest to obtain justice for Anne. It develops that Anne was killed by her Immortal ex-lover, to keep her from revealing his secret. After Tessa is taken to a police safe house, MacLeod realizes that the killer is in fact the Chief of Detectives, and he must rescue Tessa and bring justice to Anne's killer.