With the attainment of magmatic fuel, humanity destroys the Earth’s surface with excavations, and soon they create the plant-less “Plantations”. But one day, monsters known as “Klaxosaurs” started to rampage Earth, prompting humanity to create piloted robot weapons known as “FRANXX”.
Hiro’s real name is Code 016, and he was born and raised in the “Garden,” where children are cultivated to be perfect paired pilots for the FRANXX and combat the Klaxosaurs. He and his friends lived with that being their only purpose -- if they fail, they’re deemed useless. After failing to be compatible with his partner, Hiro falls into despair and finds a mysterious girl with horns asking him to be her “darling” partner!