A descendant of one of Duncan's teachers comes to him claiming a long-ago promise of help, that pits Duncan against cruel Immortal Michael Kent.

An old girlfriend of Richie's reappears, claiming he is the father of her son.

Immortal Paul Karros, who is leading a group of Balkan revolutionaries, comes to the U.S. to try to obtain arms. When a fellow traveler, Father Stephen, is shot, Duncan becomes suspicious of Karros' agenda. Also, Duncan becomes interested in Anne Lindsey, the doctor who treats Father Stephen . Meanwhile, Charlie takes an interest in Mara, a young woman who is helping Karros with his cause.

Duncan feels guilty because he could not prevent the theft of the jeweled cross or the murder of the priest in whose charge it was, so he pursues the Immortal thief across the years to restore it.

Michelle, the 18-year-old adopted daughter of one of Duncan's friends, is a not-yet-Immortal until she totals her car and wakes up in the morgue. Duncan tries to comfort her grieving parents and teach her about being Immortal, but Immortal Axel wants to use her and eventually take her head, as he has done to other young woman Immortals.

Immortal Brian Cullen, once Duncan's friend and the best swordsman in Europe, has lost his nerve for fighting and has turned to drugs and alcohol to cope with his problems. After he crashes his car into a bus while chasing after Richie, Duncan attempts to help his old friend get his life together. Also, Duncan asks Anne to dinner after accidentally causing her to fall off her bike while he is jogging.

Duncan and Richie come across an immortal who originally died when he was ten years old, and is therefore stuck in a child's body forever. Realizing that he will be an easy target for full-grown immortals, they decide to protect him.

Duncan's Immortal friend David Keogh wants to marry Jill, but she is terrified of him and asks Duncan's help to get David to leave her alone.

Duncan is having nightmares and hallucinations of fighting against a shadowy figure wearing a dark, hooded robe. When he meets an old Immortal friend, John Garrick, at Garrick's art show, he discovers Garrick had the same hallucination. Anne wants to know why Duncan has no medical history. Will Duncan gain control of his mind, or is there something more to the problem?

A mortal lawyer named Robert Waverly videotapes Duncan beheading another Immortal, then threatens Duncan with exposure unless Duncan kills Waverly's wife. Meanwhile, the cohort of the Immortal who Duncan killed wants revenge.

To save his own life, Immortal Benny Carbassa promises to deliver Duncan to an aging gangster who wants to bury a secret that Duncan knows about. Meanwhile, Anne decides that she won't push Duncan to know more.

Watcher Rita Luce is using Watcher information to help Immortal Michael Christian catch other Immortals when they are helpless so he can take their heads, and Duncan is next on her list. Meanwhile, Joe struggles with his conflicting loyalties to the Watchers and his friendship with Duncan.

In San Francisco, Immortal-turned-religious-leader John Kirin pushes a man out of the path of an out-of-control car and is hit himself, "dying" in Anne's emergency room. As Anne tells his anxious followers that he didn't make it, he walks up behind her, and they believe that it is a miracle. Duncan is appalled that an Immortal would violate the rules like that and goes looking for Kirin, who he once knew as Cage, an Immortal who always put his greed ahead of the good of mankind. Duncan and Joe don't believe in his conversion, nor does the reporter who is out to prove that Kirin is a fraud. In flashback to 1937 Spain, Duncan is covering the Spanish Civil War with Cage, who sells out the partisans to the fascists. In flashback to 1975 Cambodia, Duncan is trying to get a group of orphans out of danger, but Cage refuses to unload his drugs from a chopper to evacuate the children.

Start of the Kalas cycle. Duncan and Anne attend a musical performance by a group of European monks, led by Duncan's old friend Immortal Brother Paul. Paul discovers that Immortal Kalas is the promoter who arranged the tour, so that he could get Paul off holy ground and settle an old score by taking his head. In flashback to 1658 Europe, Duncan finds a monastery run by Brother Paul where Immortals can retreat, and Kalas is the chief singer as well as a copyist. Another visiting Immortal, Timon, gives Duncan "Macbeth" and offers to teach him to read it. Later, Duncan suspects Kalas of treachery, and he and Paul confront Kalas. In modern day, Kalas concentrates on getting to Duncan by hurting those he loves: he frames Anne for the deaths of two patients and Joe for selling drugs at his bar.

In this continuation of the Kalas cycle, Duncan has fled to Paris and meets up with Hugh Fitzcairn. Fitz is madly in love with Naomi, a fellow culinary instructor at Le Cordon Bleu, but her ex-boyfriend Patrick is determined to win her back no matter how he has to get Fitz out of the way. In flashback to 1637 Verona, Fitz is pursuing the daughter of Duncan's employer, and Duncan is ordered to get Fitz out of the way. In modern day, Kalas has followed Duncan to Paris. Continuing his plan to torment Duncan by hurting the people he loves, Kalas uses Patrick as a pawn to frame Fitz.

Immortal Kalas is after Methos, the semi-mythical oldest Immortal, to take his head and become indestructible. Duncan is determined to find Methos first.

Thugs kill Immortal Ceirdwyn's mortal lover Steven, and she vows revenge. Meanwhile, as Duncan and Maurice are watching Richie at the racetrack a young pickpocket named Paolo, who is the brother of one of Steven's murderers, steals Duncan's wallet, but Duncan catches him and winds up taking him home. On the way, Duncan learns of Ceirdwyn's situation, and he attempts to get Paolo to tell him where the rest of the gang is so that he can stop Ceirdwyn from killing them. Also, Richie pushes his motorcycle racing too hard, and he must deal with the consequences. In flashback to Roman Britain, Ceirdwyn's Pictish tribe attacks Roman soldiers, who decimate them and turn Ceirdwyn Immortal. In flashback to 1746 Scotland, Duncan tries to get Bonnie Prince Charlie safely out of the country, with Ceirdwyn's help.

Anne arrives in France to meet Duncan, but she goes into doctor mode when a young woman collapses behind her in the airport. At the hospital, they discover that the woman was smuggling heroin inside her body for the Russian mob, and that she collapsed because the balloon burst inside her. After a hit man attempts to kill the woman in order to keep her from talking, Anne tries to convince her to testify against the mob boss, but Duncan has second thoughts when he realizes that the boss is Kristov, an immortal he once crossed paths with. Meanwhile, someone recognizes "dead" Richie, so he has to get out of France fast. Also, Anne attempts to come to terms with Duncan's immortality. In flashback to 1750 Russia, Duncan is invited to stay with Kristov's Cossack band, but he is appalled when the Cossacks slaughter a defenseless band of farmers.

When a young foreigner is chased into his Paris church by white supremacists, Father Bernard sees a man he remembers from his youth in Nazi-Occupied France and thought long-dead. In flashback to 1943 Paris, Immortal Ernst Daimler is a Nazi officer and Duncan is part of a Resistance group based at a monastery. While Duncan leads the Resistance group as they ambush a Nazi courier, little Bernard sees him shot, die, and revive, but Duncan binds Bernard to secrecy. In modern day, Father Bernard realizes Daimler is also an Immortal and asks Duncan to help stop Daimler, who is now the leader of a white supremacist group working for a cause within the system. Also, Anne tells Duncan that she is pregnant, but Duncan isn't sure if his lifestyle can allow for raising a child.

In Paris, Maurice's niece Simone helps her Immortal boyfriend Lucas Kagan with an art heist that leaves two guards dead. Duncan goes to ransom the drawing and insists on meeting the boss. In flashback to 1930 Paris, Duncan is in a bank when Kagan and his Immortal mentor Tarsis rob it, leaving several people shot. Duncan fights Tarsis but lets Kagan off. In modern day, Duncan follows Simone to the bordello where she works, and he finds Kagan there. Kagan refuses to fight Duncan, saying that he might be different if Duncan had mentored him, but he never had a chance, and he asks for Duncan's help in finding redemption.

Amanda helps Kalas escape from prison so she can kill him, but he escapes and kills another Immortal to take his sword. In flashback to Algiers 1653, Xavier St. Cloud kills Duncan's teacher Hamza. In modern day, the widow of a slain Watcher is planning to expose Immortals, and Kalas' thugs capture Amanda.

Kalas kills Christine and her newspaper editor to obtain the computer disk with all Immortal and Watcher records. In 1753 Turkey, harem girl Amanda is about to have her hands chopped off for theft but Duncan rescues her. In modern day, Kalas gives Duncan a choice: let Kalas take his head, or have the Immortal/Watcher information automatically sent to every newspaper in the world. Meanwhile, the Watchers frantically search for Kalas and the disk.