The story begins with setup by Daffy Duck, playing Jack's role:
"Now there goes a salesman - he trades me out of a perfectly good, grade A homogenized Holstein cow, and for what? Three stupid beans. Jack, you're a jerk."
Subsequently he tosses out the beans and they land right into Bugs Bunny’s rabbit hole. A beanstalk erupts shortly after, and Daffy decides to climb it. During his climb, he meets Bugs who is in bed, and kicks him away, not wanting him to interfere. "I don't remember any rabbit in Jack and the Beanstalk," Bugs comments, "but there's gonna be one in this one!".
Meanwhile, Daffy reaches the top of beanstalk, excited about stealing the fortune that the giant's castle holds, until he meets the giant himself, who turns out to be Elmer Fudd. Daffy's excitement turns into fear and he runs from the giant just as Bugs reaches the top. As Elmer closes in on the duo, Bugs tells the giant to get Daffy instead, because Daffy is playing as Jack. Daffy frantically tries to pass this off as a lie, and that Bugs is Jack. Elmer decides to capture both of them and takes them to his castle, where he traps Bugs and Daffy under a glass cake cover. However, they manage to escape because Bugs has a glass cutter with him. Elmer then continues to chase the two around his castle as they are trying to escape. The chase continues until Bugs manages to trip Elmer, knocking him unconscious. Bugs wants to go home; however, the greedy Daffy decides to stay so that he can steal from the giant. As Bugs is running towards the beanstalk, he comes across Elmer's carrot garden ready to be eaten. As a very full Bugs is resting under a half eaten, giant carrot, he wonders what became of Daffy, who is shown inside the giant Elmer's pocket watch, acting like the minute and hour hands