Duncan MacLeod is an immortal who has been out of the game for many years. Duncan and his girlfriend Tessa are targeted by Slan Quince, an evil immortal. Duncan is convinced by his friend and fellow immortal Connor MacLeod that he must return to the game to protect Tessa, and to keep from losing his head.
Duncan bails Richie out of jail after he was caught stealing files from an adoption agency in an effort to find out who his parents are. From what Richie read in the files before he was caught, he and Duncan are able to find a man who claims to be his father. Duncan senses that something isn't right, so he hits the streets to find out who this man really is.
A friend of Richie's dies suddenly after being captured during a diamond heist. The police believe it to be a drug overdose, but Richie insists his friend would never have done drugs. Duncan believes it to be the work of a potion developed by Kiem Sun, an immortal he once knew.
Sensing danger, the immortal Lucas Desiree requests a visit from his old friend Duncan MacLeod. Lucas is beheaded just before Duncan arrives, and the murder is pinned on a shell shocked Vietnam veteran. Duncan knows this man to be innocent, and that another immortal is to blame. To avenge his friend and to prevent an innocent man from going to jail, Duncan sets out to find the real killer.
On his way home from the grocery store, Duncan is the victim of a hit and run. He is rushed to the hospital in critical condition, but due to his remarkable recovery time he is able to check himself out shortly after he arrives. This is noticed by a doctor who drugs and kidnaps Duncan so that he can experiment on him. Meanwhile, reporter Randi MacFarland is hot on the trail of Duncan's disappearance.
Richie saves an old friend from Russian mobsters after a drug deal goes bad. Unbeknown to him, she takes the drugs and the money with her. It is up to Duncan to protect her and her daughter from the mobsters, who are now looking for her.
While browsing Duncan's antique store, a mysterious woman named Rebecca Lord inquires about a sword that he once took from a rival immortal named Walter Reinhardt. Duncan agrees to let her test the sword, and he is shocked to find that she uses the same style as Reinhardt. Having never taken Reinhardt's head, Duncan fears that the two may be working together to defeat him.
A friend of Tessa's is assaulted and nearly killed by a serial killer who scalps his victims. Duncan believes him to be a copycat killer who is basing his crimes on those of an immortal whom Duncan confronted years ago.