Lamune is an ordinary fourth‑grade boy who loves playing video games. After buying a game from a peddler girl and helping her sell the rest, he goes home and defeats the game called “King Sccasher.” The peddler girl then emerges from the TV screen, calling him “the Blood Relative of the Chosen Hero Lamuness.” She is actually Princess Milk, who takes him to the Hara‑Hara World, where his mission is to revive the Guardian Knights. To accomplish this, Lamune must locate and unlock a shrine that contains Tama‑Q, a robot that becomes his advisor and the key to freeing the Guardian Knights. All of the Knights are autonomous mechas, except for King Sccasher, which is piloted by Lamune himself. He faces opposition from Don Harumage and his minions.