The Rangers come face-to-face with a familiar threat from the past. In the midst of a global crisis, they are called on once again to be the heroes the world needs.
When Trini, the Yellow Ranger, is killed, the Mighty Morphin Power Rangers are called back into war nearly 30 years following their successors. Rita Repulsa manages to return as a super powered robot out for revenge using a time warp to ensure the Power Rangers are killed before ever being summoned to become Rangers. Trini's daughter, Minh, sets her mind on killing her mother's killer.—ScoreArtist
In 1993, five ordinary teenagers were selected by the powerful space entity Zordon to protect the Earth from the evil witch Rita Repulsa. Thirty years later, many more have taken up the mantle as the universe's protectors, known as the Power Rangers.
Billy Cranston lays injured on a clifftop, surrounded by dozens of Putty Patrollers under the command of Rita Repulsa, reformed in a robotic body. Billy rises to his feet and morphs into the Mighty Morphin Blue Ranger as Rita orders her putties to finish him. Billy fights valiantly, but is overwhelmed by the putties and Rita, who blasts him back with her wand. As the putties approach, Jason Lee Scott, Tommy Oliver, Trini Kwan, Zack Taylor, and Kimbery Hart teleport in front of him, already morphed into the Red, Green, Yellow, Black, and Pink Rangers. Billy had already called them for help and lured Robo Rita into the open so they could find them. The Mighty Morphin Power Rangers spring into action, working together to battle the army of putties. Billy gets close to Rita and smashes her metal faceplate. Angered, Rita counter attacks, and shoots him again with her staff. While Billy is down, Rita decides to use some of her life power to create a bolt of deadly energy, and sends it hurling at the Blue Ranger. Seeing this, Trini jumps in the way to protect him, and is killed. Rita retreats to gather her strength, promising to return, and leaves the five remaining rangers devastated at the loss of their friend.
Jason, Kimberly, and Tommy go to the Dark Dimension to look for Rita. At Trini's house, Zack and Billy argue about what to tell Trini's teenage daughter, Minh. With her mom gone, Minh has no one left. Billy thinks they should tell her the truth, including that her mother was a power ranger. Zack insists that Minh is only a kid, and this sudden revelation could be too much for her, not to mention Zordon forbade them from ever revealing their identities. Billy argues that Zordon would approve in this case, as Minh would see through any lie they could try to concoct, and there is no easy way to tell her that her mother has been killed. Minh walks in as they are debating, and hears this. As she runs off, Billy tells Zack they have to explain everything.
One year later, Minh is training her Kung Fu outside. Zack has retired from his career as a congressman and become Minh's legal guardian. Meanwhile the rangers have spent the past year hunting down Robo Rita, but have so far found nothing. Zack reminds her that they are supposed to meet the others at the cemetery to commemorate Trini. As they approach the graveside, Minh thanks "Uncle Zack" for everything he's done for her, and they ruminate on the previous year's events. They suddenly hear the others call on their morphers, and rush up to find them facing down Robo Rita, along with two of her reconstructed monsters, Robo Minitaur, and Robo Snizzard. Rita has brought along a large mechanism, and is ready to put her plans of world domination in action. The rangers attack, and Zack tells Minh to stay in cover while he morphs to join them. They battle it out with the monsters, and Rita gives Snizzard a signal. Snizzard bites Jason, paralyzing him and wrapping him in snakes, which shrink him down. Jason is given to Rita and placed into her machine, and Snizaard soon does the same with Tommy and Kimberly. Outnumbered and outmatched, Zack tells Billy they need to retreat. They demorph and, along with Minh, get into Billy's car; the Radbug 2. The monsters try to stop them by blocking the road, but Billy activates the car's flight, and they soar away to safety. Rita promises that soon, they and all other power rangers will join Trini. Back at the house, the two rangers try to figure out what Rita's machine does. Whatever it is, Billy suspects that it will take their friends' lives. Minh want's to go after Rita and destroy her, but the two men tell her she cannot join them in this. Minh feels it is her right to avenge her mother, but they are worried she will get herself killed as well. When Billy points out that she is not a ranger and they cannot risk losing her, Minh blames him for her mom's death, and argues that if it weren't for him, Trini would still be alive. She storms off, and Billy and Zack head to Billy's tech company, Cranston Technologies, to get the equipment they need.
On the moon, Rita's palace has been rebuilt. The powers of the three captured rangers are draining too slow, so she orders Snizzard and Minotaur to find and capture more. Minotaur can track power rangers once they are morphed, so Rita decides to lure them out. Deep beneath Cranston Tech, the Command Center is also rebuilt. Zack and Billy enter to find Alpha-9, the latest iteration of Alpha robots, tending the monitors. He greets them, but Billy is absent. Zack asks him if he is okay, but the Blue Ranger feels guilty about what Minh said, and agrees with her that Trini's death was his fault. Zack rejects this, but Billy recalls that day. One year previous, Billy works in the Command Center with Alpha-9's predecessor, Alpha-8. Having constructed a plasma tube, they attempt to reconstitute Zordon from any trace of him that remained after his sacrifice in the Z-Wave. They get a lock on something, and thinking it's their long lost mentor, they initialize the process. Something forms in the tube, but soon causes tremors in the building and breaks free, consuming Alpha-8. Alpha knocks Billy away and is taken over by Rita Repulsa, who uses her magic to transform the robot into her new body. Billy is shocked to see their old enemy, and she tells him that the Z-Wave scattered her essence along with Zordon's, until Billy gave her a path back. She attacks him, and he escapes outside, calling the others. Back in the present, Zack tells Billy that they need to focus on stopping Rita before she can hurt anyone else. The alarm sounds, and they see on the monitors that legions of putties have begun attacking all over the world. Billy commands Alpha to initiate their contingency plan, the Bandora Protocol. Alpha sends out the alert to all power ranger teams to prepare for battle. Two rangers teleport directly to the Command Center; Katherine, Tommy's wife and the second Pink Ranger, and Rocky, the second Red Ranger. Rocky is tired from his shift as a firefighter, and Kat has left her and Tommy's son J.J. at his karate camp. They suspect the call is one of Billy's emergency drills, but are soon brought up to speed with the situation.
Back home, Minh is training furiously, frustrated that Zack will not let her join him. She sees the Putty attack on the news. Resolved to fight, she takes her mother's morpher and goes to help. At the Command Center, Billy tells the others they need to prepare in case their zords are needed. While the Saber-Tooth Tiger Zord has been reconfigured to work without a pilot, the Pterodactyl and Tyrannosaurus Zords need rangers to operate them. Alpha presents Rocky and Kat with secondary Power Coins, connected with the Morphin Grid, that should allow them to morph. Despite the risk involved in using duplicate powers, Kat and Rocky are ready to rejoin the fight. The four rangers morph, and teleport into the city to confront the putties. Angel Grove is in chaos as the putties attack civilians. The rangers start fighting them off, shepherding the populace to safety. In Rita's base, Minotaur detects the morphed rangers. He and Snizzard appear on Earth to try and catch them, and Rocky nearly gets bitten before Billy helps him escape. With the civilians safe, the rangers teleport away. Minotaur continues to track them, but he and Snizzard are overheard by Alpha who has been monitoring the fight on local security cameras. He contacts the rangers all over the world and tells them that the monsters can track them while they are morphed, they only way to escape is to power down and retreat. The Mighty Morphin Rangers finish saving the people of Angel Grove, and do as Alpha says, demorphing and teleporting back to the Command Center before Snizzard and Minotaur can catch up to them. Back at headquarters, Alpha detects Rita's base on the moon as it gathers energy. The team get a transmission from Adam and Aisha, who are fighting the Troobian Empire in space. Unfortunately, they are too far away to teleport back and help, but they are on their way. With civilians all over the worlds still in danger, Rocky wants to head to the moon and face Rita head on. However, as long as Snizzard and Minotaur are after them, they cannot morph. They come up with a plan to trap the monsters, but Zack notices Minh fighting the putties alone at Ernie's Juice Bar and Youth Center.
Minh fights off a large group of putties and clears the way for the teens at the youth center to escape. She tries to use the yellow morpher, but it does not respond to her. Despite her best efforts, she is eventually surrounded and subdued by the footsoldiers until Zack arrives with Rocky. The two older rangers defeat the putties, and take Minh back to the Command Center. Kat has found what they need for their plan, so Rocky and Billy teleport out to meet her, leaving Zack to talk with Minh alone. He makes her hand over the morpher, and berates her for disobeying him and putting herself in danger. He tells her he never wanted to reveal their ranger lives to her, it was Billy insisted she needed to know the truth. Minh feels that Zack is being hypocritical, since he and the others were all fighting the bad guys at her age. She claims she knows the responsibilities of being a ranger, but Zack recognizes that she only wants revenge on Rita, and points out that Rita herself is only after revenge. He tells her that the only way to be a hero is to set aside her anger, towards Rita, and towards Billy. He tells her about Zordon and how much he meant to all of them, which is why Billy was trying to bring him back when the remnants of Rita broke through instead. Minh takes it all in, and Zack asks her to stay put for now.
In a junkyard, Billy supercharges a crane magnet, and Kat lifts it into place. The three morph, and wait for Minotaur and Snizzard to show up. On the moon base, the monsters have captured more rangers from around the world, and set them into the machine. The device is nearing full charge as Minotaur detects Billy, Kat, and Rocky. The robotic monsters go to find them, and are caught in the super magnet. With the monsters out of the way, they meet the others and prepare to infiltrate the moon palace. Minh doesn't understand why they don't just destroy Snizzard and Minotaur, but Billy explains that finishing them when they are trapped is not the plan. The adults take handheld invisibility shields that Billy developed for Adam and Aisha, and Alpha teleports them to the moon base. Minh decides to end the monsters herself, and takes Trini's morpher and one of the invisibility shields to sneak out of the Command Center. She takes the Radbug 2 and finds civilians in danger. She runs over the putties attacking them, and accidentally activates the car's flight mode. She makes it to the junkyard and finds Snizzard and Minotaur, still trapped. She attempts once again to morph, but the power coin does not bond with her. Rita appears, amused at finding another teen trying to play hero. Minh uses Trini's Praying Mantis Technique to fight Rita, but is no match for the space witch.
On the moon, the invisible rangers easily take down the putties guarding the machine. Billy warns them not to remove the captured and miniaturized rangers, as disconnecting them from the device while Snizzard's snakes are attached to them could kill them. The will have to destroy Snizzard in order to safely remove their friends. Before they can leave, Zack and Rocky see a vision in the energy created by the machine, which shows Rita's space dumpster that she was released from all those years ago. Billy realizes that Robo Rita's device is a time machine. Rita appears behind them, along with Minotaur, Snizzard, and a captive Minh. She tells them that she will go through the time portal and give decades of knowledge to her younger self, but not before slaughtering Jason, Zack, Billy, Kimberly, and Trini before Zordon can recruit them as power rangers. Billy secretly summons his blade blaster and signals Zack to attack Rita. He fires on Snizzard, but the snake lizard monster is too quick and dodges him. Zack, Rocky, and Kat try to take Rita down, but she brushes them all off before throwing Billy to the ground with her magic. She gloats in Trini's sacrifice to save him before, and forms the killing spell once again. As she fires, Minh breaks free from Minotaur and leaps in the way, taking the shot. She is knocked to the ground, unresponsive as the others desperately try to revive her. Suddenly, the yellow morpher glows, having seemingly protected Minh from the deadly spell, and Minh sees memories of Trini's time as the Yellow Ranger. She wakes up, and the Saber-Tooth Tiger Power Coin bonds with her. Her honorary uncles invite her to sound the call, and the five rangers morph and summon their power weapons. The Power Rangers make quick work of Rita's putties, but they cannot destroy the machine until Snizzard his snakes are defeated. Robo Rita throws Snizzard out onto the lunar surface and uses her magic want to grow him giant. While she is distracted, Billy runs her through with his power lance, seemingly disabling her. The Blue and Yellow Rangers call Alpha to send them their Dino Zords, who awake from their hiding places and teleport to the moon, assembling into Megazord. Billy and Minh get into the cockpit, and Billy shows her how to pilot the massive zord as they clash with Snizzard.In the palace, The Black, Pink, and Red Rangers finish off Minotaur, and join the others in the Megazord. Snizzard is a tough enemy, and it takes all of their abilities to hold him off. Meanwhile, Robo Rita reactivates, and her time machine is fully energized. She opens the time portal, and sees the astronauts approaching her space dumpster, and setting Rita Repulsa free. The rangers summon the Power Sword and end Snizzard, breaking his hold on their fellow rangers. Rita is about to go through the time portal and join her younger self, but the rangers appear behind her as Minh pins her to the wall with her daggers. Billy and Rocky disconnect their friends from the machine, and Kat obliterates it with her power bow. As the portal closes, Zack destroys Robo Rita with his power axe. With the threat finally over, they return to Earth.
In the Command Center, Alpha tells Adam and Aisha that the rescued power rangers have been put into their ship's medical bay, awaiting transport to Aquitar to help them recover. Adam asks Billy if he will be coming with them, as Cestria misses him. He tells them that he still has business to attend to on Earth, but assures them he will return once the rangers are back to full strength. Aisha welcomes Minh as the new Yellow Ranger, and she, Adam, Rocky, and Kat say their farewells as Alpha teleports them home.
Later, Zack, Minh, and Billy are at juice bar, and Billy gives Minh her very own wrist communicator. Zack leaves to get smoothies, and Billy asks Minh if she wants anything from space when he leaves. She asks him not to stay away too long, telling him that Trini always missed him when he was gone, and admits that she will miss him too. She apologizes for what she said about her mom's death being his fault, and tells him that he shouldn't feel guilty, thanking him for telling her the truth about Trini. He in turn thanks her for saving his life, and she replies that he is family. When Zack returns, Minh tells them how the morpher showed her memories of her mom when it got blasted, and she could tell how much they all meant to her. Billy and Zack start to tell Minh stories of their adventures with Trini, who eagerly takes in every word.
In a flashback, Kimberly and Zack sing a song they wrote to their friends, Jason, Billy, Tommy, and Trini, in honor of their unbreakable bond with eachother.