The Four Heavenly Bomber Kings, minions of evil, have opened the "Gate of Seal," which controls the stability of the world, causing great disasters across the globe. Volcanoes erupted and storms raged all over the world. The air became stagnant, the earth dried up, and the water became increasingly cloudy. One day, during a battle with the Four Heavenly Bomber Kings, Shirobon, a mischievous and mischievous boy, accidentally transforms into Leo Bomberman, the star warrior of the constellation Leo. His grandfather, Grandpa Shirobon, a former hero, tells him that there are twelve heroes, including Shirobon. Hearing that if all 12 of them join forces, they might be able to save the world from the current crisis, Shirobon sets off on a journey to find allies! Will he be able to meet his 12 companions? And what exactly is the goal of the Bomber Four Heavenly Kings? A battle-packed, ultimate combined mecha manga!