Keith Winter is a scarred veteran of humanity's war against the alien Gazaria Empire, profoundly traumatized by the loss of his entire platoon, a burden that impacts his subsequent military actions. Though yearning to leave combat behind, military command reactivates him when the Gazaria Empire invades Emerald Earth. He assumes command of a special operations unit, leading elite specialists in countering the invasion.

His personal life bears the weight of familial tragedy. His sister, Maria, perished during the invasion's early stages while trying to prevent the reckless child Barney from rushing toward enemy forces; her fatal shot during this event establishes enduring tension between Keith and Barney. Barney's presence persists within Keith's unit despite lacking tactical value and displaying frequent recklessness. In the story's conclusion, Barney refuses evacuation, choosing instead to guard Maria's grave—repeating the impulsive act that caused her death—a decision made under Keith's oversight.

Keith leads the unit through the Emerald Earth campaign, engaging in direct combat against Gazaria's cyborg stormtroopers and psychic superhumans.