Long before the events of Gunnm, the young Yoko grows up on Mars in a world devastated by war, scientific experiments, and power struggles between rival factions. As the conflicts unfold, she is confronted with violence, loss, and manipulation that gradually shape the person who will later become Gally. At the same time, her past becomes intertwined with the events that shaped the history of Mars and with the origins of several key figures in the saga. Through battles, revelations, and political conflicts, Mars Chronicle explores Yoko’s roots and the circumstances that formed her identity long before her fall to Earth.