Several years after the defeat of Dr. Hell, the surviving members of the secretive mecha pilot team known as the Mazinger Angels have traded their battle gear for a more peaceful, yet covert, existence. Maria Fleed, the former pilot of the powerful Minerva X, now poses as a student at Paradise Academy. She is watched over by the school’s new nurse, the ever-capable Sayaka Yumi, once the pilot of Aphrodite A. Their quiet new life is disrupted by the sudden appearances of Saucer Beasts, strange flying craft that begin attacking the area. A new menace has arrived on Earth: the Vegan Empire, a hostile alien force. Their mission is to locate the lost princess of the planet Fleed, who they believe escaped destruction and now hides somewhere on Earth, as she holds the key to a devastating secret weapon.

Into this tense situation arrives Kikunosuke Abashiri, a rebellious and hot-headed tomboy who transfers into Maria’s class. Kikunosuke is constantly at odds with the prim and proper Maria, creating a tense rivalry. Unbeknownst to her, Kikunosuke is the heir to a powerful legacy. She possesses a special motorcycle, a gift from her father, which she soon discovers is actually a Pilder control unit. The Pilder guides her to a secret hangar containing a massive war machine designed by the late genius Professor Juzo Kabuto: the powerful and iconic robot, Iron Z, an early prototype design related to the legendary Mazinger Z. As the Vegan Empire’s Saucer Beasts attack the school, Kikunosuke is forced to pilot Iron Z to fight back, all while Sayaka and Maria mobilize their own mechas, revealing to the new girl the existence of the Mazinger Angels.

As the Angels, now joined by Kikunosuke, battle the Vegan Empire’s forces, they uncover the truth behind the aliens’ search. The princess they seek is none other than Maria herself, a fact she has kept hidden. A unique birthmark on her back is actually a star map, leading to the location of the ultimate weapon of Planet Fleed. Initially, the Angels struggle to coordinate, with Kikunosuke’s reckless piloting of Iron Z clashing with the team’s more experienced tactics. Hikaru Makiba, the original pilot of Diana A, has since retired from active duty to work as the creator of the Angels’ organization, providing support from the sidelines. However, as the Vegan threat escalates, the team must unite. Their most notable arc culminates in a desperate battle on the Vegan Empire’s moonbase. There, the Angels and Kikunosuke use the map from Maria’s birthmark to unlock the Fleed weapon, a powerful new asset that combines with Iron Z to form a spaceship capable of reaching the enemy stronghold. In a final, furious assault, the combined forces of the Mazinger Angels and Kikunosuke’s Iron Z fight to annihilate the Vegan command and secure peace for Earth.