Two astronauts open a dumpster on the moon and release Rita and her evil minions. Zordon, an interdimensional being, and Alpha 5, Zordon's robot assistant, teleport 5 teenagers to their Command Center and give them morphers with the power of the dinosaurs. The five teenagers are Zack, Kimberly, Billy, Trini, and Jason. The rangers have incredible large robots called the Dino Zords, which combine into the Megazord. The original rangers also have weapons that combine into the Mega Blaster.

Rita gives the sixth Power Coin to Tommy, a master in martial arts. The Green Ranger goes to the Command Center and makes a huge mess by making Zordon disappear. After a long battle against the elusive Green Ranger and finally recovering Zordon, the rangers finally break the evil spell on Tommy. He decides to join them and become the Green Power Ranger. He helps the rangers with the power of the DragonZord, which combines with the Megazord to form the Dragonzord in Battle Mode and the DragonMegazord. After working together for a long time, Green Ranger has no choice but to transfer his powers to Jason, the Red Ranger. He returns back when the rangers lose their power coins to Goldar when trying to save their parents.

Lord Zedd, the master of this universe arrives and kicks Rita off the moon. He sends a fish monster to destroy the original zords. Zordon gives the rangers the new Thunderzords, which combines into the Thunder Megazord. Green Ranger loses his powers and becomes the White Ranger, the ranger of Light and controller of the White Tigerzord, which combines with the Thunderzords to form the Tiger Megazord. The rangers need additional power, so Zordon sends down Tor the ShuttleZord, which forms the Thunder Ultrazord.

During their first incarnation, the Power Rangers were known as The Mighty Morphin' Power Rangers. The group originaly consisted of five teenagers, Jason , Zack , Billy , Trini , and Kimberly . They were selected by Zordon to protect the Earth against the evil threats of Rita Repulsa. The teenagers used devices known as Morphers, powered by Power Coins, to transform into the Power Rangers

The Mighty Morphin' Power Rangers commanded the mighty Dino Zords and Jason was their leader. The group was expanded to six members, when the Rangers freed Tommy form an evil spell and he joined the group as the Green Ranger. Tommy stayed on as the Green Ranger, until his powers were taken away by Rita's magic and the Green Candle. Tommy's Green Ranger powers were eventually returned to him, but were never quite the same and required him to recharge them often.

During the second season, the Power Rangers were confronted with a new enemy, Lord Zedd. To face this new challenge, their Dino Zords were infused with the Power of Thunder, allowing them to transform into the Thunder Zords. Initially, Tommy did not receive a new Zord, because his fleeing Green Ranger Powers could not handle them. Later in the Season, Tommy was restored to full power as the White Ranger. The White Ranger was the new leader of the Power Rangers and was given command of the White Tiger Zord.

Also, during the second season, Jason, Zack, and Trini were summoned to a peace conference, which forced them to give up their roll as Power Rangers. Zordon selected three new teens and through a power transfer, utilizing the Sword of Light, Aisha, Rocky, and Adam became Power Rangers.

During the third season, Rita's brother, Rito comes to Lord Zedd's palace to help Lord Zedd and Rita destroy the Power Rangers. He manages to completely destroy the Thunder Zords. This forces the Rangers to quest for a new source of power, so they seek out Ninjor. They are given Ninja Power and new Zords, known as the Ninja Zords. With these new Zords the Power Rangers face Rita and Zedd once again.

Later in the season, Kat is introduced as a villain under one of Rita's evil spells. She is eventually turned to good and after Kimberly leaves to persue her gymnastics career, Kat becomes the Pink Ranger. Also, during this time, the Rangers gain control of the Shogun Zords.

Master Vile, Rita's father, eventually joined forces with the evil villains. He came to Earth in search of the Zeo Crystal, an artifact of great power. The Rangers manage to stop Master Vile from recovering the Zeo Crystal. They break the crystal into sub-crystals and send each piece back through time.

Rita's father finally manages to defeat the Power Rangers by moving back time on Earth and transformed the rangers into children, leaving them helpless. In this time of need, Zordon calls upon the Alien Rangers to help Defend the Earth.

The Alien Rangers and Billy develope a device, using the Power Coins, to age the Rangers back to their real ages. Billy is restored to his original age, but before the others can be restored, the device and the Power Coins are destroyed. The only hope for the Rangers now is a quest for the Zeo Crystal. So, the five young Rangers journey into the past to recover the five pieces of the Zeo Crystal.

In the first Power Rangers Movie, The Mighty Morphin' Power Rangers the Movie, the Rangers faced off against Ivan Ooze, and his Tengu warriors. Ivan Ooze destroyed the Command Center and nearly killed Zordon, causing the Power Rangers to lose their powers. In order to save Zordon's life and gain new powers, they journey to a distant planet in search of the Great Power. Here they meet Dulcea, who aided them on their quest by revealing their animal spirits and making them Ninjetti. The Power Rangers eventually claimed the Great Power and with it new Ninja Zords. They returned to Earth to defeated Ivan Ooze and save Zordon's life. (The movie is on a different timeline then the series. It takes place after the second season of the Power Rangers, but does not integrate with the rest of the seasons.)