A beautiful young woman, Felicia Martins, throws herself to her death, only to revive with the realization that she is an Immortal. She seeks out Duncan MacLeod as her mentor, and becomes amorously involved with Richie Ryan. But there is much more to this "ing�nue" than meets the eye. She is in fact a long-time Immortal, engaged in a wily scheme to trap MacLeod and acquire his Quickening. MacLeod must see through her subterfuge in time to protect not only himself, but also Richie.

MacLeod stumbles across the trail of an Immortal, Xavier St. Cloud, who has lived in hedonistic splendor down through the ages by remorseless robbing and killing innocent men and women. MacLeod had nearly fallen victim to this remorseless killer behind the front lines during World War One, when Xavier used poison gas to loot a payroll truck. He uses even deadlier gas in modern day Paris, and MacLeod must track him down before he kills again. He succeeds in defeating Xavier, but the Evil Immortal escapes with his head. In a humorous yet touching subplot, Richie falls for a glamorous older woman, not realizing she is married, and Tessa must disentangle him from the woman's clutches.

A day at the circus reunites MacLeod with a former lover, the Immortal femme-fatale, Amanda, who has always meant big trouble for him. Amanda, meanwhile, is in trouble of her own as her former partner, Blaine, has escaped from prison and wants her head. She plays the two Immortal men against each other, drawing MacLeod into a daring, high-stakes burglary she and Blaine are plotting.

Tommy is an innorcent bystander who's accidentally killed during a swordfight between MacLeod and the Immortal Gallen. Haunted by the unnecessary death, MacLeod tries to find out more about the dead man -- and discovers he isn't exactly the innocent bystander he appeared.