In a distant past, Industria thrived peacefully under a single royal lineage until encounters with extraterrestrial beings sparked five decades of conflict, leaving the royal family barely in control of the planetary capital. Meanwhile, Astro the Destitute ekes out a living in the slums of the capital to support his surrogate family. His fate takes a dramatic turn when the runaway heir, Baruji, approaches him. Bearing an uncanny resemblance in voice and looks, Prince Bulge proposes a daring plan for Astro to stand in as the prince while Baruji seeks freedom from his royal shackles. Before Astro can fully grasp the situation, the prince's entourage seizes him, mistaking him for Baruji, and whisks him back to the planet. Thus commences Astro's journey of mistaken identity, catapulting him into the role of the crown prince and the planet's unlikely savior amidst the ongoing interstellar conflict.