The World's Championship Fight is about to begin in a gigantic boxing stadium. Tonight's fight features the battle between the Champ, "Battling McGook" (identified as "The Crusher" in subsequent cartoons), and his challenger "Dyspectic McPlaster". During the fight, Crusher does not even give his challenger a sporting chance. Bugs Bunny heckles Crusher enough to come up behind him. When Bugs calls to Crusher to pick on somebody his own size, Crusher decides Bugs will do, and throws him through the Dressing Room and into a corner of the ring. Bugs admits it was a mistake to open his "big fat mouth".
In the ring, Crusher shows off his muscles by bulging his biceps and getting muscles on his muscles. Unimpressed, Bugs tries flexing his muscles, which are only grape sized.
The bell rings to start Round 1. Bugs comes up to Crusher pretending to give him a sporting chance. Amused at Bugs' inexperience, Crusher just punches Bugs back to his corner. Bugs charges and gets pushed back twice. Bugs then decides to pull off a little "stragety." Coming back to the center of the ring, Bugs fakes fainting. When Crusher looks over him, Bugs punches Crusher up to the ceiling. The bell then rings to finish Round 1.
While Bugs relaxes, Crusher decides to cheat by building a brick boxing glove over his right hand. The bell then rings to start Round 2. Just as Bugs and Crusher come towards each other, Crusher punches Bugs in the face with his brick boxing glove, sending Bugs back to his corner. Just as Bugs is "kissing the canvas," the sportscaster starts the count, but Bugs snatches his microphone and immediately starts describing action that's not taking place, confusing Crusher long enough to trip over him. Angered, Crusher pulls off his gloves and comes to the center of the ring, which makes Bugs pull off his gloves (stuffed with horseshoes) and come to the center of the ring. The two of them wrestle, with Bugs picking Crusher up and then getting flattened by Crusher's weight. Bugs then gets himself flapped out again, and begins trying to pull Crusher's leg, while Crusher plays solitaire with cards. Knowing this is not getting him anywhere, Bugs takes a plank and breaks it, making Crusher think Bugs broke his leg. Bugs comes in disguised as a doctor and, after a fake examination, the prognosis being: "A compound fracture of the left clavichord, with complications yet", wraps up Crusher from head to toe in the bandages. Then, he punches Crusher so that Crusher bounces off the four poles of the ring, making "Tilt" flash up as in a pinball machine.
Throughout the rounds that pass, Bugs and Crusher fight using unsporting methods from greasing skates to firing cannons. Sometimes Bugs, sometimes Crusher or both getting beaten.
Then in Round 110, Crusher ties Bugs to a railroad track, hurries up the tracks and fetches a steam train. Now dressed as a train engineer, Crushers starts to go towards Bugs head on. All Bugs can do is start sweating and watch as the train comes closer and Crusher gloat over his intended victory.
Just than when it looks like the train is going to hit Bugs, the film appears to fall out of its sprockets and then it "breaks". Bugs comes onto a solid-white screen and (in a similar gag like in My Favorite Duck) breaks the fourth wall by apologizing to the audience for the inconvenience, but admits the film "didn't exactly break". He then takes out a pair of scissors and gives the audience a smirk at iris-out.