The Mouse That Roared plot
"They're taking over the country in an invasion of laughs!"
The Duchess of Grand Fenwick decides that the only way out of her country's economic troubles is to declare war on the United States, lose it, and accept foreign aid. They send an invasion force to New York, which arrives during a nuclear exercise that has cleared the streets. Wandering around looking for someone to surrender to, they come across a scientist with a special ultimate weapon that can destroy the world. When they capture him and have his bomb, they are faced with a new opportunity... What do you do when you win a war?