When a young high-school student named Kenta Date becomes the champion of the arcade video-game 'Megaranger,' a company known as INET (International Network of Excel-Science and Technology) invites him to their laboratories. Who was also chosen were his school friends and members of the Cybernetics club, Miku, Kouchiro, Chisato, and Shun. However, soon after a small tour of the INET HQ, the building comes under attack by the evil Neijireija, an evil dimensional force lead by Dr. Hinelar, with designs on conquering this reality. Dr. Kubota, INET's chief, reveal that Megaranger was not only a videogame, but actually a combat simulator to select the recruits to become a super fighting team to combat against the Neijirejia. Kenta, Miku, Shun, Kouchiro and Chisato become the fighting team known as Denji Sentai Megaranger. After a brief fight against Yugande, the Megaranger are forced to retreat from the exploding INET headquarters, taking off within the Galaxy Mega. Later, the evil Guirail, sent by Javious, injures Yugande in a battle with Megaranger. Dr. Hinelar poisons Guirail, turning him into Mad Guirail. The Megaranger abandon the damaged Galaxy Mega and fly the Delta Mega to the INET Moonbase where INET member Yuusaku created the Space Mega Project. The Rangers destroy Guirail with the new Mega Voyager, comprised of five transforming Voyager Machines. Soon, Yuusaku becomes MegaSilver.
Dr. Hinelar then creates the evil Nejiranger, secretly draining energy from Javious the First after both Nejirangers' and Javious's destruction. Later, Dr. Hinelar creates Nejirejia City. The Nejiranger are later resurrected but turned into data cards. Dr. Hinelar learns the Megarangers' identities, and Shibolena accesses INET database and locates the moonbase. Yugande gains a new, more powerful, red form with a special circuit, and attacks the moonbase, forcing the main five Megarangers to flee, Yuusaku stays at the moonbase to work on repair the Voyager Machines that were buried in the rubble. Dr. Hinelar turns into a monster form, and the Grand Nejiros base transforms into the Death Nejiros. Yuusaku is able to finish the Mega Voyager and sends it to the Megaranger. Hinelar self-destructs Death Nejiros, destroying Mega Voyager high above the city. The Megaranger were forced to risk their lives to prevent any damage to the city by carrying Death Nejiros into the sky. However, in the end, the Megaranger survive, and celebrate their High School graduation with Dr. Kubota and Yuusaku.