Intergalactic chickens invaded Earth, seeking revenge for the oppression of their earthly brethren. They came out of nowhere, and everywhere. It was only you who managed to repel the invasion, and saved humanity from an eternity of servitude. For centuries we cooked, fried, stewed & baked them in in pies. But the day of revenge came & they invaded the Earth. Fight for your right to have omelets & cakes with fillings or become part of the menu in a chicken restaurant in the boundless expanse.
They came without warning, squawking menacingly their ruffled feathers darkening the sun. Invading intergalactic chickens out to punish humanity for our oppression of their earthly brethren three times they invaded each time with increasingly devious plans. So get ready for your greatest adventure on its way.