In a single night, the "Pulse" swept across the globe. Every female human experienced a total cognitive collapse, their higher reasoning, speech, and memories dissolving into a primal, instinctive void. They didn't become monsters; they became strays. Driven by basic needs—warmth, hunger, and a desperate, biological urge for touch—they now wander the silent cities. They perceive the few unaffected (the "Keepers") not as equals, but as masters, sources of food, and objects of intense, animalistic fixation.