It's present in the game version 1.05 or higher.
You are Ed Winter, a US Army pilot sent deep behind enemy lines to execute a covert operation.
A non-canonical story: what if the US entered into a war with Russia? What if they engaged in full-scale war? What if global conflict is inevitable?
The AH-64 - a modern, fully-armed army attack helicopter
Surprise - a large-scale military operation risks developing into something else altogether. Can you adapt to survive?
Arma 2 or Arma 2: Combined Operations.