In the year 3000, a fugitive named Ransik evades capture from the Time Force. He injures Red Ranger Alex and travels back in time to conquer the past. Time Force operative Jen, Alex's fiancée, steals five morphers and a time ship, and along with teammates Katie, Trip, and Lucas, travels to the past in search of Ransik. In the year 2001, they recruit a new Red Ranger named Wes, an ancestor of Alex, and they all become Power Rangers for the first time to defend the city of Silver Hills against Ransik.
Wes and Jen get jobs painting at a TV station, which they find out is being taken over by Ransik to broadcast his presence to the city. When Wes is captured, Ransik takes the opportunity to tell him his origin, which involves genetic tampering of newborns in the future. The Rangers save Wes, and defeat Ransik's latest criminal mutant.
A couple of moving violations prompt Lucas to get his driver's license. While taking his road test, he runs into Nadira, who just robbed an armored truck with her new supercharged cars. The Rangers bring out their Vector Cycles, chase down Nadira, disable the cars, and capture her mutant cohort.
Nadira's latest mutant kidnaps a group of kids and holds them for ransom. Wes steals money from his father to get the kids back, but as usual, the villains don't keep their word, and the Rangers must battle to get them back. Wes realizes that he needs to find his own path in life, and leaves home to live in the clock tower.
When Nadira kidnaps Circuit, the Rangers are out of luck when a giant sized mutant doctor named Medicon attacks the city. Trip uses his powers to find Circuit, and repairs him just in time to defeat the mutant with their Zords.
Memories of Alex drive Jen out of control, as she goes on a dangerous solo mission to get revenge on Ransik. She not only ends up almost getting killed, but also ends up almost killing a mutant named Fatcatfish.
When Frax unlocks the infamous X-Vault, he unleashes his own dangerous mutant on the city. Katie has doubts about fighting for a world that is not her own, but she eventually gets over it, and the Rangers defeat the new mutant menace by combining the Time Shadow and the Time Force Megazord into the Shadow Force Megazord.
Trip's lack of physical prowess make him question his abilities as a Ranger. Ransik unleashes Electropede, who can drain the energy from the Rangers' weapons. Trip proves his worth by creating the Electro Booster, which Wes uses to defeat the power hungry mutant.
Mr. Collins unveils his new task force, the Silver Guardians, of which an old schoolmate of Wes ', Eric, is a member of. When the Guardians interfere in a battle, Wes' identity is discovered by his father, who urges him to follow a different path in life.
Eric and Wes follow Commandocon back in time, where they all struggle for control of the Quantasaurus Rex. The mutant prevails, and takes the Q-Rex to present day Silver Hills to wreak havoc. The Rangers cannot defeat the Q-Rex with their Zords, but Eric breaks it free of the Commandocons's control and uses it to destroy the mutant.
Nadira kidnaps Dr. Zaskin, Bio-Lab researcher of Ranger technology. She then goes after his daughter, who has found protection with Lucas. While Lucas battles a mutant to save the girl, the other Rangers, along with the Silver Guardians, rescue Zaskin.
Katie encounters a ghost named Walter in the clock tower, who sends her back in time to change his lonely fate. She meets Walter in the past, and changes his future by helping him stand up for himself and attain the woman he loves.
A blunder by Wes has Jen doubting whether she can trust him or not. Ransik's new mutant sends the Rangers into another dimension, where they fight a team of evil Rangers. Only by trusting each other are Wes and Jen able to work together to free everyone from the dimension.
Trip helps out a peaceful mutant who is being hunted down by Frax for refusing to fight for Ransik, and hunted by Eric for being a mutant. Eric's change of heart leads to him helping Trip free the mutant of Frax's control, and putting him back on ice.
Contemptra places the male Rangers under a love spell, making them fight over her human form, Angelique. With three Rangers distracted, Ransik attacks the city. The girls drive off Ransik, and break Contemptra's hold on the guys before putting her on ice.
Lucas' old friend Dash, a mutant criminal ex-race car driver, teams up with Nadira for a rash of thefts. After a period of emotional and physical hostility, Lucas makes Dash see the error of his ways, and the mutant turns himself in.
An ambitious photographer named Mitch discovers the true identities of the Rangers. Katie begs him not to hand in the pictures for publishing, but it takes a near death experience during a mutant attack for Mitch to have a change of heart and give Katie the pictures.
The Rangers are duped into watching the filming of an action movie, where they are ambushed by Cinecon and sent into other dimensions which mirror their favorite types of movies. By destroying Cinecon's clapboard, the Rangers are freed from the dimension, only to face the director himself in a giant sized battle. The Rangers successfully rewrite Cinecon's movie, and put the mutant on ice.
Steelix, Jen's old Time Force partner, seeks revenge on Jen for getting him locked up. He steals her morpher, fights her on her own, then turns her evil. Wes breaks Jen out of the spell, and all of the Rangers defeat Steelix.
Frax releases Venomark, who infects the city and four Rangers with the same poisonous bite he gave Ransik many years ago. By snagging one of Ransik's vials, Wes is able to get the serum reproduced by Bio-Lab, saving his friends and the city.
Out of serum, Ransik raids Bio-Lab to steal their supply. He succeeds, and injures Mr. Collins during the break-in. Frax, who is on the run from Ransik, works on building his own giant sized robot. After fending off Ransik's forces, the Rangers are approached by Alex, who tells them that their actions are changing the future.
Alex reclaims his role as Red Ranger, as Wes leaves to see his father in the hospital. Alex organizes a pre-emptive strike against Frax's new robot, Dragontron, making him retreat with the help of Eric and the Q-Rex.
Alex finally realizes that the Rangers need Wes to defeat Dragontron. With Wes back as the Red Ranger, the team manages to destroy Frax's creation. Alex also saves Mr. Collins from death, and learns an important lesson in making your own destiny.
The Rangers go undercover at a gym to discover that Frax is using it as a front to turn its customers into robots. With help from Eric, the team defeats the mutant running the gym, and rescues the customers.
A misunderstanding leads Nadira to fall for Lucas, who is threatened by Ransik to treat her well. After forcing a breakup, Lucas is attacked by Chameliacon, who is defeated with the help of the Rangers.
After helping to deliver a baby, Nadira has doubts about hating humans. Frax is captured by Ransik, turned into a mindless robot, and forced into piloting Doomtron against the Rangers. As Eric and the Q-Rex fight Doomtron, Wes tricks the Rangers, and forcefully sends them back to the future for their own safety. Doomtron incapacitates Q-Rex, leaving a injured Eric on the run with help from Wes. The two retreat to the clock tower, which is raided and destroyed. The Rangers take control of their fates, and go back to help Wes. As a team, they destroy Doomtron. Their final battle with Ransik ends with Ransik turning himself in after nearly killing Nadira. The Rangers part ways as the four leave to go back to the year 3000.