Jerry hypnotizes Tom to be more harmless when His tail is pulled, but with a bad side effect if His tail's pulled too hard...
Inside Tom's house, Tom is chasing Jerry yet again, and with the Kitten capturing the mouse in the Kitchen, and flinging Him in the mouse hole. inside, We see Jerry under a mess of books, and He sees a book on Hypnosis, which gives Him an idea. Jerry comes to a sleeping Tom and Hypnotizes Him, into being considerate and harmless when Tom's tail is pulled. the hypnosis was successful, and pulls Tom's tail. Tom wakes up, and grabs Jerry. however, the Kitten removes a flea from Jerry's head, and lets Him go. in the Backyard, Tom and Jerry play a game of croquet. everything went good until Tom accidentally whacked the croquet ball too hard, smashing through Spike's fence, and bonking Spike on the head. The Bulldog comes and grabs Tom by the tail, but as Spike was about to do physical harm on the unfortunate Kitten, Tom's eyes become red and becomes monstrous, clobbering Spike, making Him run away in a panic. Jerry pulls Tom's tail to make Him stop, and He did stop, return to normal as He went to sleep. to make Sure Tom wouldn't get in more trouble, Jerry pulls Tom back safely in the house.
Inside, Jerry reads more on the hypnosis book, and realizes that hypnotizing any animal of a younger age, and that if the victim's tail is pulled too hard, the Victim will go into a rage, until His tail is pulled again, as long as it's more gentle. Jerry continues to read the book and realizes that to remedy Tom's Hypnosis, It said See the Book, "Curing Hypnosis", which Jerry doesn't have, so Jerry goes to the library to write down the way to end the hypnosis. as Tom sleeps, He wakes up and finds a ball of yarn, then plays with it. In the Library, Jerry sneaks inside the Library and writes down the last details on lifting Tom's hypnosis. and runs away with the paper after a Library guard spots Him.
as Tom sleeps in His bed, His owner is about to drag Him out, but pulls His tail too hard, which causes Him to go berserk and cause chaos outside the house. Jerry returns and sees Tom brutally beating a tree, fortunately, Jerry pulls Tom's tail and returns to normal. Jerry then undoes the Hypnosis He put on Tom, and with Tom free of the hypnosis, He grabs Jerry and rolls Him to the mousehole, satisfied with having Tom not being hypnotized, as the Kitten returns to His bed.