- The story begins with a Commander trying to get an "eight-engined Navy hydroplane" through a storm (1). He is a brave and unstoppable man and clearly has the admiration of his crew.
- Of course, this scenario turns out to be little more than a fantasy in the mind of Walter Mitty, who isn't so much piloting anything as he is driving his wife into town. Mrs. Mitty complains that he's going too fast.
- Walter drops his wife off to get her hair done and gets ready to do the list of errands she's prepared for him. Mrs. Mitty reminds him not to forget to buy his overshoes (rubber rain boots) and insists that he wear his gloves while driving.
- Mitty drives away and is chastised by a cop for dawdling while putting on his gloves. He drives past a hospital and launches into another fantasy. This time, he's a famous doctor trying to save a millionaire and friend of the president's named Wellington McMillan.
- In this fantasy, Mitty is introduced to the other doctors performing a surgery on the millionaire. They both express their admiration for Mitty as a doctor. When one of the machines breaks during the operation, Mitty deftly uses a fountain pen to fix it, buying the surgeons ten minutes to continue. When the other doctors get stuck, Mitty steps in to save the day.
- Walter's fantasy is interrupted by a boy shouting at him to back up. It seems he entered the parking lot through the exit lane. The parking attendant just tells him to leave the car there, and he'll park it properly.
- Mitty leaves the car and muses that people like that parking attendant are always so arrogant. He remembers once trying to take the chains off his tires himself and getting them tangled. The mechanic grinned at him the same way the parking attendant did. Now Mrs. Mitty makes him drive the car to the garage every time he wants to remove the chains.
- Next time, thinks Walter, he'll wear his arm in a sling so that the men at the garage won't laugh at him.
- Walter remembers that his wife wants him to buy overshoes and makes the purchase at a shoe store. Then he can't remember the second thing his wife told him – twice – not to forget to buy. As he runs through a list of possible items, Mitty decides that he hates these weekly trips to town that they make.
- While he's thinking, a newsboy goes by shouting about the Waterbury trial. This leads Mitty into another fantasy. This time, he's a great pistol shot being interrogated in a courtroom. His defense lawyer argues that Mitty could not have killed the victim, since his right arm was in a sling on the day the murder took place. But Mitty interrupts his lawyer and shouts that he could have killed the man with any gun of any make with his left hand from three hundred feet away.
- "Puppy biscuit," says Walter Mitty. He suddenly remembers the thing he's supposed to buy – puppy biscuits. A woman going by laughs at him and thinks he's a crazy guy who just said "puppy biscuit" to himself for no reason.
- Mitty goes into a store to buy puppy biscuits, but can't remember what the right brand name is. He has to describe what the box looks like to the clerk.
- After his purchase, Walter goes to the hotel lobby to wait for his wife. He notices a copy of Liberty magazine with pictures of German bombers on it.
- Mitty fantasizes that he is an Air Captain, willing to sacrifice his own life for the good of his country.
- Walter is interrupted by his wife's arrival. She scolds him for not putting on the overshoes he bought. "I was thinking," responds Mitty. "Does it ever occur to you that I am sometimes thinking?" (14).
- Mrs. Mitty responds that she is going to take his temperature when they get home.
- The two of them leave the hotel lobby together. Mrs. Mitty runs into a drugstore to grab something, and Walter is left standing against the wall outside. He imagines he is about to be shot by a firing squad, but faces it boldly and bravely.