Nobody knows how it started. Some said it was from infected meat, others claimed it was a Russian chemical weapon, and some believed it was divine punishment. Everybody searched for an explanation for the hell that had unleashed on America.

Creatures hungry for human flesh—zombies, undead, demons—whatever we called them, they came when people started dying and rising from graves. The air reeked of decay, and the streets echoed with guttural moans that chilled survivors to the bone.

The media alerted the population too late. Defense lines collapsed, and within weeks, the major American cities were invaded. Survivor accounts revealed scenes of chaos, violence, and despair. The stench of death permeated everything as people fled to the countryside, but the virus was everywhere. The United States collapsed. The government attempted to establish quarantine zones, but the military forces were quickly overwhelmed. Communication networks crashed, and citizens were left to fend for themselves. Groups of survivors tried to organize, but distrust and paranoia set in like a sickness worse than the infection itself.

Information about the outbreak reached overseas, but the contagion's speed prevented an effective response. Europe, Asia, and Africa, although initially spared, took drastic measures. Borders slammed shut, quarantines went into place, and frantic efforts to develop vaccines began. America became the playground of the undead, ruthless human gangs, and scavenger groups that were sometimes even worse than the zombies.

Ryan was sprinting among the burned cars on the main avenue, the acrid smell of smoke still clinging to the air two days after his parachute drop onto a New York rooftop. The sound of distant gunfire echoed between crumbling buildings as he moved silently, his boots crunching on broken glass.

Sent on a top secret mission, his superiors had told him nothing about the person he was supposed to bring back to the safe zone outside American territory. He knew only to recover the scientist in the downtown laboratory and bring them to the outskirts for helicopter extraction. Ryan wasn't the type to ask questions, but he couldn't help wondering about the scientist's importance and praying they were still alive.

He entered an eerily well-preserved building, the cool interior a stark contrast to the sweltering summer heat outside. The stairs creaked under his weight as he climbed to the 8th floor of the old high-tech laboratory, his rifle ready as he eliminated the few zombies that shuffled toward him, their rotting flesh making squelching sounds with each movement.

Arriving at a solid steel door, he took out the key he'd been given and inserted it into the lock. The mechanism clicked loudly in the silent hallway as he turned it.