Jerry Jerry lounges in a chaise longue, reading and nibbling cheese off a mousetrap. When his doorbell rings, he opens the door and finds a small, young mouse named Nibbles. A note pinned to Nibbles' red scarf states that Nibbles is the orphan Jerry had agreed to host for Thanksgiving. A postscript on the note warns:
> He's always hungry.
Jerry's cupboards are empty, so he carefully leads Nibbles to a bowl of milk in front of where Tom is sleeping, and holds him over the bowl. Nibbles takes a loud slurp, awaking Tom, but Jerry pulls Nibbles back into hiding. Tom does not see anyone, so he drinks his milk and goes back to sleep. Jerry holds Nibbles out to catch the last big drop that falls from Tom's whisker, but the bowl is now empty.
Then Jerry and Nibbles see Mammy Two Shoes place a large turkey on the already laden table. The two mice climb onto the table, and Nibbles begins to take bites of all kinds of food, exposing himself to risks Jerry has to rescue him from. Using table decorations, Jerry and Nibbles dress as pilgrims with hats and a blunderbuss. Nibbles then swallows a whole orange, swelling him, but Jerry hits Nibbles on the back of the head, causing the orange to fly out of Nibbles and into Tom's mouth, waking him up.
Tom, seeing the mice getting into the Thanksgiving dinner, puts on a feather duster, first as a general camouflage, then as a Native American headdress. Tom approaches Nibbles, who points his toy blunderbuss at Tom. Tom lowers his chin, daring him to hit him, until Jerry pops a champagne cork right into his face. Tom then grabs Jerry, but Nibbles, carrying a fork, ricochets off a jello and stabs Tom in the hind end. Tom in turn uses the fork to catch Nibbles, and Jerry whacks Tom in the face with a large spoon, knocking him back.
Sneaking back to the table, Tom sets a bowl of cattails on fire one at a time, throwing them like spears. The cattails burn or melt the various hiding places Jerry and Nibbles find. With the third one, Jerry lifts a serving dome, which reverses the cattail back toward Tom. Then Tom throws a knife into the turkey; Jerry runs into the blunt edge and knocks himself out.
Nibbles now launches an all-out attack: he bends back a knife handle to launch a pie, and using a string between the turkey's legs, he slingshots a candle, which lands on Tom's tail and burns him up to a crisp. Then he cuts a cork off a champagne bottle, which rockets at Tom and launches him into a cabinet, destroying it and all the dishes inside. Conceding defeat, Tom waves a white surrender flag from under the pile of broken dishes.
Finally, with order on the table restored, all three sit down to dinner. After Jerry has said grace, and just as he and Tom pick up their cutlery, Nibbles goes through the entire turkey, leaving nothing but the bones on the plate. Nibbles, now finally full, pats his huge stomach in delight.
