Tom is using Jerry as a yo-yo. Tom then hears Mammy-Two-Shoes telling him that it is time to put him out for the night. Noticing that the weather outside is rather unpleasant and hearing Mammy say that if she stood in the draft she'd "catch her death of cold", Tom craftily fakes a cold, pretending to sneeze violently. Mammy asks if Tom has a cold. Tom nods and sneezes again. Mammy has a change of heart and allows Tom to sleep inside for the night, but gives the cat a stern warning that she'd wash his mouth with soap if he was lying. Tom grabs an onlooking Jerry, who appropriately shoves a bar of soap in Tom's mouth. Tom spits out a multitude of soap bubbles and chases Jerry into his mousehole, but ends up with a mousetrap on his nose. When he takes it off, his nose rolls like a window shade.
Tom prepares to sleep on the living room floor, nose bandaged up. While Tom is asleep, Jerry enters the room with a small pot of red paint, painting several red spots on his face after removing the bandage on Tom's nose. When Tom wakes up, Jerry convinces him that he has measles, showing evidence of a nationwide measles epidemic in the newspaper, and producing a mirror, showing Tom his own spotty reflection and he screams.
Jerry consults Dr. Quack's medicine book and does a number of unorthodox treatments to the now hypochondriacal cat, such as placing a stethoscope next to a ticking alarm clock to intensify Tom's apparent heartbeat and setting off the alarm shortly afterwards, and then he tests Tom's reflexes and uses a hammer by almost bludgeoning him, and he shoves a thermometer in Tom's mouth, where (out of Tom's view) Jerry holds a cigarette lighter underneath the thermometer, causing the temperature to rise, expanding the thermometer, such that it explodes.
The next chapter of the medical book urges Jerry to apply chills to Tom's high fever. Soon Tom is in the freezer, teeth chattering. Jerry unloads a spoonful of ice cubes onto Tom's body and puts a spoonful of ice cubes into his mouth, and then closes the freezer door for a few seconds. As he opens the door, a frozen-solid Tom slides out of the freezer. Jerry panics and looks at the following book's advice on extreme chills, then shoves Tom into the oven, turning it onto a low temperature. Opening the oven door, Tom is now conscious, but still very cold, and baking in his own juices and grease. Jerry pours some juice and grease over Tom and then closes the door, adjusting the oven's temperature. When he opens the door again, Tom is bright red and burning. Jerry quickly touches the hot cat and burns himself. Thinking quickly, he places Tom onto a baking tray and heads for the bathroom, giving him a cold shower.
Tom later emerges from the shower, covered in towels and using hot-water bottles as sandals. He observes himself in the mirror and notices that most of his spots have gone. As he wipes his forehead, the final two spots are removed and transferred to his paw. Just then, Tom sees a small jar of red paint hidden in the corner, while Jerry puts the book down and tip-toes from him, Tom paints three spots on his head, which realization dawns on him; his mirror image changes to a donkey jackass. Tom becomes furious after realizing that he was tricked, grabs a sword and ready to get back at Jerry. He finds the mouse sitting hunched-up with head in hands, looking very depressed somehow and he only blinks at Tom apathetically when prodded with the sword's keen point. Only when Tom snatches him up does Jerry break out in genuine measles spots, which proliferate before Tom's horrified gaze. Tom quickly dashes to the bathroom and wash his hands and then doses himself frantically with everything he can find from the medicine cabinet (throat sprays, pills, mouthwash, nasal drops, etc., but little does he know that there is no cure for measles), while a sped-up version of George Frideric Handel's Death March plays over.
By the end, both the cat and mouse are covered in spots from head to foot and being quarantined by Mammy Two Shoes herself. Tom pouts and glares at Jerry for making him get measles. Then Jerry holds up a mirror and sticks out his tongue which is too covered in spots. That may also imply that Jerry got a more severe case of the measles than Tom did, he then leans by the window on the windowsill.Directed by: William Hanna and Joseph Barbera
Animation: Kenneth Muse, Ed Barge, Ray Patterson, Irv Spence
Layout: Richard Bickenbach
Music: Scott Bradley
Produced by: Fred Quimby
DVDTom and Jerry's Greatest Chases, Vol. 4
Tom and Jerry Spotlight Collection Vol. 2, Disc One