A company called Farm and House has delivered Muriel's kitchen curtains, as well as a complimentary packet of seeds. Eustace claims that nothing has grown at the farm in 50 years, and throws the seeds out the window, where it destroys Courage's sand castle. While upset over the destruction of his sand castle, Courage plants the seeds anyway. A raincloud appears out of nowhere, and showers Courage and the soil. A flower blooms, then rapidly evolves into a big tree, complete with beautiful flowers. Muriel is amazed, but Eustace is angered that Courage could grow something and he never could.
Muriel's pie is burned in the kitchen oven, and she wishes for a new oven. Courage, while wearing a gas mask, notices that a new oven has appeared next to the tree. He gets Muriel and Eustace's attention and they notice the oven also. Muriel tells Eustace to bring it in, which he does, but not without effort and a cracked back. Muriel thanks Courage for the new oven and the tree. This causes Eustace to grow angry.
Courage is playing with his toy construction vehicle, but it breaks. He wishes for a real construction vehicle, which spawns next to the tree. Courage and Muriel are then shown having great fun in the vehicle, digging up dirt and dumping it elsewhere on the farm. This wakes up Eustace, who comes out of the window and exclaims that he is trying to take a nap. Frightened, Courage accidentally dumps the dirt on Eustace, who is heard muttering "Stupid dog."
Later, while Muriel and Courage are sitting outside next to the tree, Eustace intends to go to the picture show, claiming that he isn't wanted around the farm. Muriel wishes that she and Courage could see a movie, and this causes a projector to form out of the branches, which starts playing a horror movie. Eustace notices this from the truck and tries to ram it into the tree. Muriel stops him, and explains that the tree is providing for them, which Eustace says is his job. Later, when Muriel and Courage have gone to bed, Eustace comes back out to take the rocking chair inside, insults the tree, and wishes that Muriel had a bigger head so that "she'd know better."
The next day, Muriel is laying on the couch with an extremely engorged head. Worried (not because of Muriel but because he is hungry), Eustace calls Dr. Vindaloo. The doctor explains that it is the worst case of "boli-boli" he has ever seen. He does "everything known to medical science", which involves a rubber glove, a mallet, a huge pair of scissors, and a wrench. The doctor tells them that there is nothing to worry about, but there is nothing he can do about it and exits the house, while Courage and Eustace look at him, dumbfounded. Courage howls in desperation, but Eustace says that it is all his fault for bringing the tree, and now he has to get takeout for breakfast. He kicks Courage out of the house next to the tree. Courage starts saying "help" to the tree, and this causes the tree to start speaking to him, which scares Courage to the point that his skin flies off his skeleton. The tree tells him to not be afraid and that it has the cure for Muriel. It will take 3 days, but by then, the tree predicts it will be cut down. It then says that "anything worth it's value is worth fighting for." Peeking inside the shed, Courage learns that Eustace plans to chop down the tree with an axe. Courage uses the vehicle he obtained earlier to dig a moat around the tree. He obtains a packet that makes a singing eel appear, then finishes by building a giant sand castle around the tree.
Finally, Eustace, in battle gear, is prepared to chop down the tree. Eustace's first attempt is botched when Courage throws marbles into his path, which he slips on and falls into the water, where the eel scares him out. Eustace then attempts to use a giant boulder to get through, and Courage puts on a baseball helmet and an bat and prepares to hit him back, but he goes through the sand castle and ends up back in the water again, where a "CRUNCH" is heard underwater and the eel once again chases him out.
By the third attempt, the fort is revealed to be nearly destroyed, but Eustace makes one last effort. He catapults himself past the defenses but lands in a boiling cauldron that Courage was stirring up, jumps out screaming and lands in the water. The eel and Eustace resurface and start singing together temporarily, but in the end the eel eats Eustace and shakes him in his jaws.
Courage is exhausted, but then gets a call from the doctor, saying that he has the cure. Courage drives to the office, where Dr. Vindaloo gives him a cure that "will cure your broken leg". Meanwhile, back at the farm, Eustace confronts the tree, who asks if cutting him down will make Eustace feel more important around the farm. Eustace thinks about it for a second, then says "Yes!"
A skeptical Courage races back to the farm, where he discovers that Eustace has chopped down the tree. Courage runs up to the top of a boulder and yells so loud that the sun shatters like glass. He comes back to the fallen tree and starts crying, but the tree comes back to life one last time to tell him that the actual cure for Muriel is composed of the flowers from its branches mixed with pure hornets honey. With those final words, the tree dies. After salvaging the flowers, Courage later climbs into a hornet's nest in a big field. The view shifts to the field, while Courage is heard screaming. Now covered in hornet stings, Courage gets the cure to Muriel, whose head returns to normal. Sometime later, a flower is shown to be growing from the stump of the old tree, while Muriel pats Courage on the head. Eustace is then shown lying on the couch, also with an engorged head as revenge for chopping down the tree. He asks "Is the tree growing back yet?"
- Eustace claims that nothing has grown on the Bagge family farm in fifty years. However, this is proven false as three episodes ago in Journey to the Center of Nowhere eggplants were grown and were featured in a competition. Although technically this was proven false even earlier as the Goose God created a field of flowers in his appearance. However Eustace did not see this happen.
- Technically, it is Eustace's fault the tree grew. If he hadn't thrown the seeds out the window, Courage wouldn't have found them and the tree wouldn't have grown.