In a devastated 1995, Earth lies under the grip of the Akron, an alien army from the Saar cluster that has left survivors scraping by in shanty towns and villages. Kento, a war orphan hiding in a cave with his friends to escape bandits, stumbles upon the secret base of Dr. Earl, a refugee from Helios, another planet the Akron conquered. Dr. Earl brought with him the finest achievement of Helian technology: Daltanious, a super robot that grows stronger when combined with Beralios, an intelligent lion robot. Kento turns out to be a descendant of the long-vanished Helian royal line, and Dr. Earl entrusts him with the fight for Earth. Alongside his friend Danji Hiragi and Beralios, Kento takes on the Akron with Daltanious in a mecha series that mixes giant robot battles with comedy.