After blowing up an alien army and saving humanity from extinction, regular guy Mulligan must figure out how to lead his fellow survivors as president.

Aboard the cruise ship, Lucy and Zhao suspect the Fun Police are up to no good. Back on land, Mulligan turns America over to the United Kingdom.

An unexpected visitor hatches a plan that could destroy humankind unless Mulligan can act fast. But all of his cabinet — except Lucy — has abandoned him.