Three hundred years after a war that reshaped human history, child soldier Mikazuki Augus works for the private security outfit Chryse Guard Security, protecting Kudelia Aina Bernstein, an activist pushing for Mars's independence from Earth's rule. When the firm's superiors betray and abandon their own soldiers mid-mission, squad leader Orga Itsuka leads the boys into open rebellion, with Mikazuki taking the controls of a salvaged Gundam to hold off the forces sent against them. This manga adapts the Mobile Suit Gundam: Iron-Blooded Orphans TV anime.