La Souris Qui Rugissait

Down-on-their luck brothers, Lars and Ernie Smuntz, aren't happy with the crumbling old mansion they inherit... until they discover the estate is worth millions. Before they can cash in, they have to rid the house of its single, stubborn occupant—a tiny and tenacious mouse.

The Duchy of Grand Fenwick decides that the only way to get out of their economic woes is to declare war on the United States, lose and accept foreign aid. They send an invasion force (in chain mail, armed with bows and arrows) to New York and they arrive during a nuclear drill that has cleared the streets.