In the bleak aftermath of Earth's conquest by alien forces, Kento, an orphan of war, seeks refuge with his friends in a hidden cave to evade ruthless bandits. Uncovering the secret lair of Dr. Earl, a refugee from the conquered planet Helios, they encounter the mighty super robot Daltanius and its intelligent lion companion, Beralios. As a descendant of the lost Helian royal lineage, Kento is tasked by Dr. Earl to wield these advanced technologies in the battle to reclaim Earth from the oppressive Akron invaders.