The chronology of Power Rangers may, at last, be at an end. A boy has arrived from the future to save the Earth from catastrophe. Shane and his team are not aware that they are part of the enemy's plans. The Ninja Strike Rangers, who once protected Earth, have returned! And this time, they believe the Humanimal are Phantom Force monsters! This battle will be the end of both teams. Will the message of the future boy get to Shane in time? An unbelievable roll call that brings together all the warriors of the Power Rangers!
The film opens on a crimson lens filtered scene of a boy running and seeing the dead bodies of the Royal Beast and the Ninja Strike Rangers on a burning battlefield. The boy laments he is too late and that the history of Power Rangers will end. Jumping back to the present time of the film, the Humanimal are enjoying some camping as the Humanimal members of the team play while Shane is flustered that no one will help him set up the camp site. An observer is watching them from the shadows and Shane tries to call Cameron, but oddly finds that his cell phone isn't working despite being in range of a signal earlier. Cameron is carrying homemade food and is going to meet up with his friends until he suddenly gets knocked over by a young boy wearing ninja garb, whom after apologizing to Cameron, races off. Cameron gets depressed the food he worked so hard on preparing is now ruined and lying on the ground. The others are preparing to cook on a campfire, but then sense the presence of and are then attacked by the Ninja Strike Rangers. The Humanimal are confused as they do not know why they are being attacked or even what a ninja is. The Ninja Strike Rangers think the Royal Beast Rangers are evil Phantom and must be destroyed and get ready to fight them. Shane tries to deescalate the situation by telling his teammates to assume their human guises, thinking this is all a misunderstanding, but this fails as the Ninja Strike Rangers believe the Royal Beast Rangers are trying to deceive them and transform. The Royal Beast Rangers recognize them as a Power Rangers team and are still confused as to why they are attacking them, but transform to defend themselves. Red Ninja Strike and Red Eagle Ranger engage in an aerial battle, while the other team members clash with each other on the ground using their various abilities. Shane changes into Red Whale Ranger when the other Royal Beast Rangers get pushed back and fires the Whale Gun, though he makes it a point not to hit the Ninja Strike Rangers directly. The blast knocks the Ninja Strike Rangers back and the Royal Beast Rangers use this opportunity to retreat. This does not help their case of being innocent however, as the Ninja Strike Rangers are more determined to stop them and summon Ninja Strike Megazord to block their escape. The Royal Beast Rangers summon Stampede Megazord and Jungle Megazord to fight Ninja Strike Megazord, but the Ninja Strike Rangers’ experience in combat and various tactics overwhelm the two robots, such as using Shinobi Striker's agility and UFO Strike Megazord. After the Royal Beast Rangers finish combining the Royalzord into Jungle Stampede Megazord, the two teams end up in a beam attack duel when the two robot's finishers collide. The resulting explosion from the colliding energy attacks critically damages both robots and both teams get knocked out of the cockpits and un-transform. Ned, being stubborn, continues to try to attack Shane despite the latter wanting to talk things over. Shane tries to run away when Ned won't listen, only to be pursued by the teleporting ninja. Meanwhile, Cameron is wandering around depressed about the destroyed boxed lunches and finds the campsite abandoned upon arriving. The other Ninja Strike Rangers are returning home and Jill cannot contact Ned on her cell phone and Norman can't seem to call Lloyd. A creature called Chum emerges from hiding and asks if the team has slain the Royal Beast Rangers, to which they say no. Chum cries as it is afraid of the Royal Beast Rangers as he claims they had wiped out his entire race. Anne and Isaac are skeptical as the Royal Beast Rangers didn't seem like the kind of hostile savages he speaks of. Chum says that is their way of tricking them and the Royal Beast Rangers are a "fake Ranger team" and cries even more. Isaac thinks they need a strategy as there are six Rangers on the Royal Beast team and they only have five at the moment. At a park near a noodle cart, Tusk tries to call Shane but his Royal Morpher is also unable to send calls. The Humanimal are again confused as to why "ninjas" would attack them and wonder again what a ninja even is. The owner of the noodle cart is revealed to be none other than Lloyd, who enthusiastically wants to explain about ninjas to them after showing off his skills, much to the surprise of the four. Shane is fleeing from Ned near a playground, when the latter finally manages to capture his prey and try to "unmask" the Phantom he believes Shane is. The boy from earlier calls out for Ned to stop, calling him "Dad". This confuses and shocks Ned, with Shane baffled as well. Back at Mr. Moore's house, Marvin is cosplaying as a frog while making a frog wood sculpture. Yellow Ninja Strike and White Ninja Strike sneak in to spy on him to see if the "Phantom" are there, but Marvin seemingly detects their presence and throws whittling knives like shuriken at them. The two Ninja Strike Rangers vanish before they are spotted and Marvin thinks what he thought were robbers was just his imagination. Yellow Ninja Strike and White Ninja Strike then see Cameron return and abduct him upon learning he was headed for the campsite where the Royal Beast Rangers were during their battle. Once outside and meeting up with Blue Ninja Strike and Pink Ninja Strike, Cameron recognizes them as a Power Rangers team based on their colors. White Ninja Strike accidentally puts Cameron in a depressed state again by saying they are the "real" Power Rangers. Anne deals with this by knocking him out and suggesting they take him back to the dojo for questioning. Chum comes by and uses vines to bind the unconscious Cameron and gag him to prevent him from screaming for help when he wakes up. Back at the park, Shane learns the boy's name is Nathan and he is from the future. Ned readily accepts this but Shane is skeptical, Nathan explains he used a time travel ninja technique to arrive in the present time. This causes Shane to nearly faint as he is dumbfounded by how little sense that makes. Ned asks his son what he is like in the future, but Nathan depressingly says Ned died and will die the next day along with the Royal Beast Rangers and the rest of the Ninja Strike Rangers if he doesn't change the past. As dusk falls, Lloyd finishes explaining what ninjas are to the Humanimal: spies that work to fight for justice. Rhino Royalzord races toward them carrying a letter and a photo of Cameron captured from the Ninja Strike Rangers issuing a demand they come to a gym to fight. Sela is fed up with the Ninja Strike Rangers as they are the ones acting like villains, which confuses Lloyd as he is a Ninja Strike Ranger. Lloyd transforms into Gold Ninja Strike to try and explain things but gets tackled and captured by the paranoid foursome who think he is trying to attack them. Back at Mr. Moore's home, Nathan explains that the Ninja Strike Rangers were tricked by an evil being into destroying the Royal Beast Rangers and the resulting conflict killed both teams and ended the legacy of Power Rangers. This means that 12 years into the future, Earth has no Ranger teams left as they were wiped out one by one by this evil force. Nathan says that he wishes to be Legendary Red Ninja Strike to protect his world like his father and grandfather did, so he came to the past so Power Rangers can exist into his time. Realizing Chum tricked him, Ned apologizes to Shane and pleads for his forgiveness in earnest, going so far as to bow on his hands and knees on the floor. Shane is fine with his apology and the two make up. Shane is mistakenly called "Red Royal Beast Ranger" by Ned but Shane corrects him and introduces himself. On the Players’ ship, Chum is revealed to be a monster hired by Dropette unofficially, as Xeno does not know of this. Chum specializes in eliminating the champions and heroes of countless planets through deception and using special pollen clouds to block communications to perpetuate suspicion, confusion and fear. Isaac interrogates Cameron about Chum's people, but the vines on Cameron's mouth distort his words and control it to seem like a confession of his "evil murderous deeds" when Cameron is trying to prove his is innocent. Inside his head, Cameron is horrified he cannot speak what he actually wants to say. Lycan, Ghari and Kifaru all try to help him figure out a way to convey his actual feelings to the Ninja Strike Rangers even though his speech is being controlled. Cameron tries to squirm and struggles to get the vines off of him so he can communicate with the Ninja Strike Rangers. The two Reds get ready to head out to stop Chum and Ned reassures his son that he'll protect his dream of being Legendary Red Ninja Strike. At the gym, the four Ninja Strike Rangers are shocked to see Lloyd as a hostage. The Royal Beast Rangers request that Cameron be exchanged for Lloyd, but this act escalates the hostile tension between the two teams and they transform and fight each other. Ned and Shane arrive and try to plead for both teams to stop fighting but they cannot hear them. The two rescue Lloyd and Cameron, but their remembrance of their abductions causes further misunderstanding as the two Gold rangers attack the opposing teams. Chum observes this from a distance and laughs as all is going according to plan. Ned decides to knock some sense into their teams by fighting them, but Shane knows that will only make things worse. Shane tries to remain calm and think as if he loses his temper or gives into the bloodlust that is affecting both teams, they are all doomed. Nathan leaves Mr. Moore's house to help his father. Despite Shane and Ned's efforts, neither team will listen with White Ninja Strike shooting her brother and knocking him out of his transformation. The two teams prepare to execute a team finisher blast and both Shane and Ned jump directy in the line of fire to try to stop them. The teams ignore them and fire a Beast Shoot and a Explosion Slash attack. As the projectiles come at the two Reds, they dodge the incoming fire and the resulting explosion seemingly kills all of the Rangers. The scene from the opening of the film replays, this time without the filter, as Nathan looks in horror at the deaths of the Royal Beast Rangers and Ninja Strike Rangers. Chum gloats, but it is revealed the dead bodies are illusion clones. The real Rangers come out of hiding and prepare to fight Chum. Anne explains that they knew of Chum's plan due to Cameron, in desperation, using the movements of his butt to write a message to take off his mask. Once removed, Cameron explained everything and Anne and the others used the clones to trick Chum into thinking everything was still going to his plan. Once they were not suspected, they went and made an apology to the Royal Beast Rangers, which the Humanimal only accepted after a lesson on ninja skills to them so they could help with the charade. They intentionally kept Ned and Shane out of the plan to make it convincing enough to trick Chum. Shane is a little upset his team lied to him, but they reassure him it was only to keep up the ruse, which depresses Shane. Enraged at being tricked, Chum reveals its true form: Grovek, the top assassin of heroes in the galaxy. Nathan is told to run by his father and he disappears. Grovek faces the Rangers outside and resurrects the generals of the Phantom Force, Lord Bane, Bangray and Sharpish as his personal army. The Rangers transform and fight, each using their combined skills in unique ways. Blue Ninja Strike uses his magic alongside Green Elephant Ranger's brute strength to overwhelm Sharpish, then changes Tusk into a smaller version of Elephant Striker to finish him off. Leo and Norman use their intelligence and impulsiveness to overwhelm Bruticus with Wild Release mode and the Alien Ranger Shuriken. The female Rangers collaborate to fight Bangray, with White Ninja Strike and Pink Ninja Strike changing into their Boost Zord forms to attack him followed by a team-up finisher to destroy him. Gold Ninja Strike and Black Keeper Ranger use the Beast Rod to "fish" away Geezer's staff and then take a selfie together. Having Gold Ninja Strike be such fast friends with him fires up Black Keeper Ranger and he goes into Great Wild Release form and Gold Ninja Strike tag team attacks with him to finish Geezer off. However, Lord Bane proves to be a difficult foe for Red Ninja Strike and Red Eagle Ranger. Nathan tries to help, but is unsuccessful as Lord Bane deflects his Lightning Attack attack back at him and the Red Rangers. The Sealing Shuriken mysteriously appears and attacks Lord Bane while Red Eagle Ranger changes into Red Gorilla Ranger. The Sealing Shuriken lands in Nathan's hand and changes into a Red Ninja Strike Shuriken, meaning history has changed and a future version of himself has become Legendary Red Ninja Strike. Thus, Power Rangers now still exists in the future. Jack appears and is panicked because the Sealing Shuriken flew out of the ninja residence on its own, demanding to know what is going on. Ned simply points at the fight going on and Jack decides to help. He is shocked that he has a grandson but then it turns into pride and joy as he sees Nathan's Ninja Shuriken. He gives his future grandson a Shinobi Blade and they transform into a three-generation trio of Red Ninja Strikes. The three Red Ninja Strikes battle Lord Bane and use teamwork to quickly defeat him.
While Grovek faces off against Red Gorilla Ranger, Dropette, Cerebros and Azald try to do a sneak attack on Red Gorilla Ranger only for Swift to arrive to stop them. Swift tries to change into Vermillion Bird Ranger. But when a red lion-themed hero calling himself Cosmo Leo comes crashing in from the sky, four more heroes drop in to help, and then the last four heroes drop in to face the three Players generals in order to prevent them from interfering. Once the generals are defeated, they ask the heroes where they came from and they introduce themselves as Power Rangers Cosmo Rescue before they leave. Swift sees this as a sign that history was successfully altered, allowing the legacy of Power Rangers to continue. With the clones destroyed, the Ninja Strike Rangers and Royal Beast Rangers join forces to defeat Grovek, who enlarges himself with some Continue Medals and decides to destroy the whole planet. The two teams then form Cetacean Drove Megazord and Rodeo Strike Megazord to fight Grovek, but the enemy easily overpowers them. Just as the heroes are about to be killed, they have a vision of the previous 38 Red Rangers, who bestow upon them the power to form Ninja Drove Megazord, that, infused with the power of all the Power Rangers, finally destroys Grovek once and for all. Having prevented his father's death, Nathan bids farewell to him and his friends before returning to the future. As the others wonder how Nathan came to exist since his father originally died in the current day, Ned deduces that his new wife must be already pregnant, revealing that he has just married, a fact that astonishes even his own family, who was unaware of it.
Power Rangers Cosmo Rescue: As the show confirmed in its 18th episode, the Cosmo Rescue Rangers do not exist in the mainstream universe. Therefore, it's impossible to place their appearance in this movie between some of the show's episodes, unless there is cross-dimensional travel involved (similar to VR Fighter's appearance in episode 7 or Cosmo Leo's appearance in the 24th episode of VR Fighter) .
With the exception of Red Protox Ranger, Rangers in the center are grouped in the following categories:
Red Mystic Ranger, Red Samurai Ranger, Dragon Shock: Rangers based on mythological animals.
Red Ranger, Red Dino Ranger, Dino Charge Red: Dinosaur Rangers.
Red Wind Ranger, Red Aquitar Ranger: Ninja powers
Galaxy Red, Cheetah Spy Ranger, Solar Flare Eagle, Red Protox Ranger, Falcon Master, Red Wild Force Ranger, Sky Wing Hawk, Jungle Fury Red Ranger, Ranger Operator Series Red: A mix of Feline-themed and Bird-themed Rangers.
Solar Flare Eagle standing next to Red Protox Ranger highlighted the fact that Royal Beast is a homage to Solar Flare.