The Phoenix remakes Astro Boy's origin not as triumph, but as an unfinished argument. Blue Bon exists because Astro Boy's mercy has limits, because a robot built to love humanity eventually meets one broken enough to hate it. The film stakes everything on a single question: can Astro Boy convince another creation to see humans the way he does, or will he have to destroy the only mirror he's ever had.

The Phoenix opens the film by recounting the adventures and hopes of Astro Boy, with much of the recap drawn straight from footage of the 1980s TV series. After this look back, Astro Boy faces Blue Bon, who hates humans because they tore apart his family, Maria and Tonto. Astro Boy tries to change Blue Bon's view of humanity, but Blue Bon misreads him and decides that anyone who will not side with him must be his enemy. When Astro Boy cannot persuade him that they need not be foes, the two begin to fight in a sci-fi action movie with mecha elements.