Episode 1
Kento and Dani face the Akron in the second battle where triumphants leave but a marching robot army based on Dr. Earl ready for revenge. The professor tells the boys about his exile of space, when he left the planet Helios invaded by Akron to take refuge in the Earth. He came to our planet in 1945 along with the Harlin prince whose traces are lost together with the robot lion made by the professor to face the enemy in the future.
Aired 28/03/1979EP 1 - Episode 1
Future Robot Daltanious
It is the year 1995. Earth has been conquered by an alien army from the Saar cluster known as the Akron. The cities of Earth have been destroyed, and the remaining survivors live in harsh shanty towns and villages. Kento, a war orphan, hides within a cave along with his companions in order to escape some bandits. In the cave, they find the secret base of Dr. Earl, who was an inhabitant of the planet Helios, a planet conquered by the Akron. Dr. Earl then fled to Earth, bringing with him the greatest achievement in Helian technology: the super robot Daltanius, whose power is increased when combined with the intelligent lion robot, Beralios. Dr. Earl entrusts the fight for Earth to Kenta, who happens to be a descendant from the long disappeared Helian royal line.
(Source Wikipedia.org)