In the wake of 'Laplace's Box' unveiling in U.C. 0097, the Universal Century Charter recognizing Newtypes failed to bring substantial change to the world. Following the 'Laplace Incident,' which saw the defeat of the Sleeves, two enigmatic psycho-frame mobile suits, the white unicorn, and the black lion, vanished to erase their threat. Yet, the reappearance of the RX-0 Unicorn Gundam 03, missing for two years, heralds the return of a legendary entity, the golden phoenix known as Phenex, stirring anew in the Earth Sphere.