Troy, the new kid in school, has a dream on the school bus of many Power Ranger teams battling an unknown enemy army. Meanwhile, the Insectoid-like race known as Warstar plans to invade Earth. Gosei, an intergalactic wizard who was an apprentice of Zordon awakens from his sleep and has his robot aid Tensou summon "a group of teenagers with attitude" to fend off Warstar's threats. The five new Power Rangers - Troy, Noah, Gia, Emma, and Jake - are summoned to Gosei's stronghold and are given their new Power Ranger gear, and then proceed to defeat the invading Warstar forces and win their first battle.
Warstar's scientist Yuffo is sent to study humanity in order to figure out how the invasion can be completed more efficiently and to discover a way to defeat the Power Rangers. Troy is approached by Creepox in the forest, trying to goad him into a fight, but Troy refuses. Yuffo proceeds to attack the Power Rangers, but they combine their weapons and are victorious. However, the alien threat is super-sized using a Warstar technology called Zombats, leading the Megaforce Rangers learn to call upon their Zords. Meanwhile, Jake tries to impress Gia, only to get nowhere.
Jake brings his Snake-Axe in a guitar case to use as a weight to strengthen himself. But when Noah has trouble lifting Jake's heavy weapon, he begins to doubt his abilities until he learns that if he believes in himself, he can do anything. Warstar sends Virox to infect humans with one sneeze, turning them into Loogies, Warstar foot soldiers, leading the Rangers to quarantine the infected. Noah's belief in his abilities enable him to unlock a new Zord combination, and is able to defeat the monster Virox. Afterward, Noah replaces Jake's heavy axe with a lighter metal for better balance, only for Jake to be initially unable to swing the axe properly.
A civilian named Jordan falsely claims to be one of the Power Rangers, distracting the real Power Rangers from their attempts to focus their concentration on training for future battles, particularly the attacks of Dragonflay. The Rangers eventually defeat the Warstar monster and Jordan eventually admits to the public that he is not a Power Ranger, later telling Troy he has learned that it is better to be himself.
The Warstar monster Beezara uses her powers to turn Gia and Emma against each other and the boys into her loyal drones.
When Dizchord attacks the city with music that produces physical pain, the Rangers must fight back in an unorthodox way with a song of their own.
Troy defends a kid from bullies that want to crush the rare insect that he has found. Afterwards, the Rangers end up in their final battle against Creepox.
Robo Knight awakens to help the Rangers when the Toxic Mutants awaken and threaten to pollute the environment with their monster Hisser.
Vrak and Psychotick capture Robo Knight in order to reprogram him to serve the Warstar.
The Megaforce Rangers must teach Robo Knight the meaning of teamwork at the time when Vrak and the Toxic Mutants unleash the powerful Shadow Serpent upon the city.
The Megaforce Rangers must find a powerful ancient weapon called the Wild Sword in the Black Mountains. Vrak plans to get to the sword first where he enlist the help of Distractor.
Gia, Emma, Troy, and Jake are captured by Nojoke during his capture of laughing people. Noah and Robo Knight must overcome their differences to free the captive Rangers and defeat Nojoke.
A dream-eating monster called Dream Snatcher preys on Emma after being powered up by the Aurora Box that belonged to Vrak's family. The Rangers and Robo Knight must rescue Emma's dreams and defeat Dream Snatcher before the Roots of Despair emitted from his victims rot the Earth.
Gosei and the Rangers must work together to defeat Bluefur and Bigs once and for all when they use the power of the Aurora Box to make themselves stronger.
Vrak's newest creation Metal Alice tries to convince Robo Knight to work for her and her robot army rather than the Power Rangers.
Metal Alice's robot Rico malfunctions and Emma and the Power Rangers try to teach it compassion.
Metal Alice plans to attack the city by derailing a train while Robo Knight learns what it means to be human when he meets a young boy.
As Robo Knight continues to explore humanity, Admiral Malkor awakens from his cocoon and heads out to destroy the Power Rangers.
Metal Alice converts Vrak into a robot/cyborg to attack the Power Rangers when she is visited by a robot known as Messenger who informs her the invasion will soon begin.
The Power Rangers fight against Cyborg Vrak, Metal Alice, and Messenger to save the Earth, even if it might cost them all of their powers.
In this Halloween special, the Rangers meet a medium whose crystal ball curiously shows them previous battles - and raises their suspicions by acting in favour of the creatures and villains shown. The fortune teller reveals his identity as a mutant named Glytcher and attempts to cause all electronics in the city to malfunction. With Emma's help, the Rangers must find a way to defeat him and save Halloween.
In this Christmas special, Robo Knight learns the true meaning of Christmas from a group of children when he disguises himself as a donated Christmas toy and is shipped in a charity crate to Africa. Once in Africa, he tells the children in an African village about his life and the heroic actions of the Power Rangers.