As the beginning credits roll, Jerry is seen mixing a potion. When he drinks the potion, he discovers he is able to run (and eat) at blinding speed.
Tom is about to eat a sardine, but Jerry gets to it first. Tom is confused, and then waves it off and goes for the rest of the fish. Jerry steals those too. Tom then sops up the last bit of fish gravy with his finger, but Jerry eats it and also takes the skin off that finger. Tom begins to wonder if it is a ghost eating his food, but he discounts this idea as stupid. He comes to the conclusion that it must be a bug with a jetpack and chatter-like teeth.
Tom slips a large watermelon slice around the corner and readies a flyswatter. Jerry mows through all the watermelon flesh and Tom only ends up scattering the rind and seeds around. When Tom sees an entire turkey being eaten, he panics and takes a grape cluster and an apple from the table. Jerry eats the apple down to the core, then comes back to eat the entire fruit and then to eat all but one of the grapes. Tom covers up the grape, then licks his lips at it and Jerry swipes it. Now Tom starts to go berserk. He hides in the refrigerator and then starts to take a sniff of a rack of ribs. He does not see Jerry swipe them all until he bites on each of the bones in turn.
Tom then sets out a cake and films Jerry stealing it so he can see who is taking his food. After Tom prepares the film, he plays it in slow motion. This is what happened:
Jerry then bounced the cherry like a basketball and then procured a net through which the cherry fell into Jerry's mouth. Jerry bounced up, dashed superfast to the right and grabbed the net so that it twisted into the word, "Fin".
Tom comes up with a plan to catch the mouse in his act. He makes a mousetrap sandwich and makes a "Mmm" gesture so that Jerry will chomp it and get trapped. Jerry does take the bait, but the trap doesn't work. Tom bites at the mouse, but ends up biting the mousetrap (which cause him to scream) and launching himself into the light fixture. Jerry brakes and raids the refrigerator. Tom follows him and opens the door to find a banana walking. Tom snatches it up and pulls the banana skin down to reveal the mouse and right after Jerry ate it. Jerry kisses Tom's nose and runs off at superspeed, but the potion wears off and throws the mouse around randomly. Jerry falls into his hole as Tom reaches for him.
Jerry makes a second potion, but this time it makes him grow and grow and grow and grow. Tom catches the mouse's tail and somehow manages to pull him through the wall. When Tom can no longer lug the load around, he turns around to see the mega-Jerry sadistically raising his eyebrows and waving at him. Tom begins to laugh at the supersized Jerry, but then begins to cry as the cartoon ends.