他们拥有梦想, dreams that one day will pierce the vast skies, veiled by glass. They dwell within a mobile fortress city called "the Garden", where they celebrate civilization. Within this urban jungle resides "Mistilte's", affectionately known as the "birdcage", housing the young pilots.
Blind to the world outside and freedom's skies, they are taught only one mission: battle. The enemy is a colossal life form shrouded in mystery called the "Kyriad". To combat an unknown foe, they climb aboard mechanical beasts called "Franxx". They believe that riding these machines proves their very existence.
Among them stands a prodigious boy, Zero One Six, known as Zorome. Once revered as the Divine Child, he now dwells in despair, a being unneeded by others. Unless he pilots a Franxx, he feels invisible.
One day, a mysterious girl with horns on her forehead, codenamed 02, appeared. "Ah, I've found you, my Darling," she whispered. Intrigued, Zorome embarks on an extraordinary journey, uncovering secrets and forging bonds, in search of his true purpose and the truth behind the Kyriad.