Ensign Shiro Amada is transferred to Southeast Asia to take command of the 08th MS Team. In their first guerilla operation, Shiro's team is tasked with distracting the Zeon forces while Federation ground troops locate a mysterious new Zeon weapon.

The Yomota family is small and typical: father Kinekuni (42), mother Tamiko (38), and son Inumaru (17). One day, a beautiful girl appears at their front door, calling herself "Maroko Yomota," granddaughter of Inumaru who travels back in time with a time machine to visit her ancestors. Despite of Tamiko's strong objection, Kinekuni and Inumaru welcome her to stay with them, and the structure of a happy family has begun to collapse.

Long ago, a powerful sentient robot known as GoLion, abused his great powers by attacking and killing creatures known as Deathblack Beastmen, boasting that no one could defeat him. For his arrogance, The Goddess of the Universe punished GoLion by separating him into 5 different lion robots. In the year 1999, a group of 5 young men returned to Earth after a space voyage, only to find it ravaged by nuclear war. After encountering the alien race known as the Galra, the 5 youths end up on the planet Altea and learn that the 5 lion robots that GoLion was split into are in hibernation in various parts of Altea. Somehow, they must reunite the lions and form GoLion, the only hope for the human race.