Black Friday is a day (usually after Thanksgiving in the United States) when people go to shop for products that are in sale or are highly discounted.
Background[]

The "Black Friday" is the codename for a bioterrorist attack that unleashes a devastating pandemic. The attack is orchestrated by a shadowy group with the intent to destabilize the United States, targeting it's economic and social heart during the peak of the holiday shopping season.
The weapon of choice is a genetically engineered strain of smallpox, dubbed the "Green Poison" or "Dollar Flu". This virus, created by rogue scientist Dr. Gordon Amherst, is highly contagious, airborne, and has a mortality rate far exceeding natural smallpox. Amherst, driven by an eco-extremist ideology, believes humanity's overconsumption and environmental destruction justify a radical culling of the population. He sees the virus as a tool to reset civilization, aligning with his warped vision of a "new world order."
The Attack[]

On November 27, 2015, during the chaotic rush of Black Friday sales in Manhattan, the virus is released. The method is insidious: contaminated U.S. currency, specifically small-denomination bills, is seeded with the virus. As shoppers exchange cash in crowded stores, the Green Poison spreads rapidly through touch and inhalation. The virus's incubation period is short, and symptoms - fever, coughing, and hemorrhagic lesions - appear within days, overwhelming hospitals and first responders.
New York City, a global hub of commerce and travel, becomes the epicenter of the outbreak. The virus spreads beyond the city as infected individuals travel, but Manhattan is hit hardest due to it's dense population and the timing of the attack. Within a week, the city is in chaos: infrastructure collapses, supply chains fail, and panic sets in as the death toll skyrockets.
Government Response[]
The U.S. Government, caught off-guard, declares a national emergency. Quarantine zones are established, with Manhattan sealed off to contain the outbreak. However, the virus's spread and the breakdown of law and order render these measures ineffective. Riots erupt, and factions - ranging from desperate civilians to organized criminals like the Rikers gang - vie for control of the city's dwindling resources.
The Strategic Homeland Division, or "The Division", a covert group of sleeper agents is activated under Presidential Directive 51 by President Waller. These highly trained operatives, embedded in society as ordinary citizens, are tasked with restoring order in extreme crises. Equipped with advanced technology and given broad authority, Division agents are deployed to New York to stabilize the city, protect survivors, and investigate the origins of the attack.