Stanley Ford leads an idyllic bachelor life. He is a nationally syndicated cartoonist whose Bash Brannigan series provides him with a luxury townhouse and a full-time valet, Charles. When he wakes up the morning after the night before - he had attended a friend's stag party - he finds that he is married to the very beautiful woman who popped out of the cake - and who doesn't speak a word of English. Despite his initial protestations, he comes to like married life and even changes his cartoon character from a super spy to a somewhat harried husband.
Jerry Lewis plays Norman Phiffer, a proud man in a humble life, who doesn't know that his girlfriend, Barbara, is heir to the Tuttle Department Store dynasty. Mrs. Tuttle, Barbara's mother, is determined to split the two lovers, and hires Norman in an attempt to humiliate him enough that Barbara leaves him. Will she ruin their love, or will he ruin her store?
American GI Ernie Williams, admittedly weak-kneed, has an uncanny resemblance to British Colonel MacKenzie. Williams, also a master of imitation and disguise, is asked to impersonate the Colonel, ostensibly to allow the Colonel to make a secret trip East. What Williams is not told is that the Colonel has recently been a target of assassins. After the Colonel's plane goes down, the plan changes and Williams maintains the disguise to confuse the Nazis about D-Day.
Insurance salesman Milford Farnsworth sells a man a life policy only to discover that the man in question is the outlaw Jesse James. Milford is sent to buy back the policy, but is robbed by Jesse. And when Jesse learns that Milford's boss is on the way out with more cash, he plans to rob him too and have Milford get killed in the robbery while dressed as Jesse, and collect on the policy.
