A lethal virus spreads throughout the British isles,infecting millions and killing hundreds of thousands. To contain the threat, acting authorities brutally quarantine the country as it succumbs to fear and chaos. The quarantine is successful. Three decades later, the Reaper virus violently resurfaces in a major city. An elite group of specialists is urgently dispatched into the still-quarantined country to retrieve a cure by any means necessary. Shut off from the rest of the world, the unit must battle through a landscape that has become a waking nightmare.

When Alex, an infiltration expert with a secret past, accidentally reveals her identity during what should have been a routine heist, she quickly finds herself mixed up in a government conspiracy and entangled in a deadly game of cat-and-mouse with a master assassin and his team of killers. Armed with her own set of lethal skills, Alex looks to exact revenge for her murdered friends while uncovering the truth.

A group of teenagers suffer a terrible accident during a joy ride and get trapped at the bottom of a ravine.