Incoming Chaos is a series of PB2 map levels, 

Incoming Chaos tells the story of a resistance group trying to defend the Earth of alien invasion led by Boss Falkok
in the first chapter, a civil security team is fighting the aliens in space, Sigma team led by a captain plans to regroup with the Alpha Team on Earth, along with a pilot of a ship they face Boss Falkok

the second chapter narrates the fight of resistance on earth