US Airdate : 19 October 2002
UK Airdate : 28 October 2002

Jesse (Forbes March) pursues the evil mutant Ashlocke (Michael Easton) from the Strand building, where he picked up a vial filled with a mysterious blue liquid. When Jesse loses him at an intersection, he radios Brennan (Victor Webster) and Shalimar (Victoria Pratt), who catch up with Ashlocke and follow him to the Ellison Psychiatric Ward. At Ellison, Ashlocke visits Diana Moller (Lindsay Booth), a mutant with the power of time travel, who is a patient at the hospital. Threatening Diana’s life, Ashlocke insists she use her powers to send him back to Oct. 13, 1978. As Diana raises her palm and creates a shimmering wall, Brennan and Shalimar appear and watch Ashlocke jump through the time travel hole. Without hesitation, the two also jump through the hole in hot pursuit. Ashlocke surfaces and immediately takes off. Moments later, Shalimar and Brennan surface and taking in their surroundings, realize they’ve traveled back in time and have landed on the construction sight of Ellison in 1978. In the present, Jesse enters Diana’s room and she tells him that it’s possible that the actions of Ashlocke, Brennan and Shalimar in the past could drastically alter the present.

Forcing Diana to go with him to Sanctuary, Jesse radios Adam (John Shea) to tell him what’s happened. Meanwhile, Shalimar uses her feral senses to locate Ashlocke, who has just stolen a getaway car. When Brennan jumps on a nearby motorcycle and takes off after him, Shalimar spots a magazine at a newsstand with a cover story about Adam. Back in the present, Adam reveals that Oct. 13, 1978 was the day that Ashlocke was given a formula created by Adam to reduce his powers in an effort to make him more human. Adam knows that if Ashlocke drinks the blue potion while in the past, he will be unstoppable. Fearing for Brennan’s and Shalimar’s safety, Adam convinces Diana to use her powers to send him and Emma (Lauren Lee Smith) into the past.
Back in 1978, Shalimar goes to Genomex in search of the Young Adam (Christopher Jacot). Meanwhile, Brennan follows Ashlocke to his childhood home and watches as the evil mutant comes face to face with his parents, as well as the 10-year-old version of himself. Knowing that the blue liquid he possesses can be used to make the Young Ashlocke (Max Morrow) invincible, Ashlocke convinces his younger self to go with him to Genomex. Brennan follows but is sidetracked when he realizes he is being followed by two policemen.

When Adam and Emma arrive in the past, Adam immediately goes in search of his younger self to warn him about the dangerous blue liquid. When he finds Young Adam, however, Ashlocke is already with him. Adam realizes that he is too late as Ashlocke has already given him the vial. An altercation ensues and Ashlocke sends a powerful psionic blast at Adam that instantly kills him. As a result of Adam’s death, the present immediately changes and Sanctuary begins to disappear. Jesse and Diana know that the only way to bring Adam back and prevent changing the present permanently is to travel back in time to the moments before Adam's death.

In the past, Jesse uses his powers to redirect the psionic blast Ashlocke shoots at Adam. The blast bounces back and hits Ashlocke instead, knocking him unconscious. When the Mutant X team is reunited, Adam takes the blue vial from Young Adam. Diana then uses her powers to return the team to the present. Suddenly, Ashlocke awakens and follows the team into the hole. When Diana and the team resurface, they can feel Ashlocke’s presence, but are more concerned about getting Diana to safety. That night, Adam resolves to hunt down and defeat Ashlocke once and for all.