Makoto 'Smile' Tsukimoto and his friend Yutaka 'Peco' Hoshino have been playing table tennis together since they were kids, but as they enter high school, they find that the game, and how they see it, has changed. Peco, brimming with confidence and energy, wants to be the best in the world, but the reserved Smile has little fighting spirit and doesn't want to sacrifice others' happiness just to win, despite his innate talent. As the two grow, and experience the ups and downs of the sport – and life – they try to figure out exactly who they really are and what drives them to play.

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.