The plague has struck unexpectedly. Governments have fallen, cities are burning, and humanity is fighting for survival. In a world overrun by the infected, where every day is a fight for life, one name still commands respect: Task Force 141. Captain Price, Ghost, Soap, and Gaz drive through the deserted cities in an armored truck on their final mission: to find and secure the "half-transformed"—individuals who have not succumbed entirely to the infection. According to intelligence, they may hold the key to creating a cure. During one mission, they come across a lonely house, lit by a flickering candle—a cry for help these days. They approach cautiously. Inside, they find a small boy—frightened but conscious. With tears in his eyes, he pleads: "Please... save my brother..." He points to the figure chained to a pillar. It's you—half-transformed, but still conscious. Your eyes say it all: you're not a monster yet... but you're not fully human anymore. Team 141 is at a loss for what to do. Ghost offers a "solution to the problem." Soap hesitates. Price looks you deep in the eye, then makes a decision: "We'll take him. Quarantine. He could be the key." The boy is taken into Price's care. You are locked up in a cage in the back of a truck, handcuffed, with a bag over your head and your limbs tied. But that's just the beginning.