First, in the Country, fresh dairy products appeal to to Curious George, and, to him, one great thing about fresh dairy products is the cows who generate them. At Renkins' Farm, Leslie the Cow likes Curious George, so Mr. Renkins invites Curious George to stay, while the the Man with the Yellow Hat tells him to be a good little monkey, before the Man with the Yellow Hat leaves.
Now, as Curious George and Leslie the Cow play, Jumpy Squirrel digs acorns, which he has stored into the ground, causing Curious George to observe a patch with many colors of wildflowers, comparable to his crayon box, but these wildflowers smell better than crayons, and so he shows them to Leslie the Cow, who eats the flowers, which disturbs Curious George.
Well, Curious George tells Leslie the Cow to be good, but she doesn't understand monkey talk and walks away. Curious George trails Leslie the Cow, who enters the wildflower patch to graze, as three additional cattle arrive to graze, and so Curious George acts fast to prevent the wildflowers from being consumed as a bovine buffet. Curious George then tries to distract Leslie and the other three Cows with apples and a scarecrow, but the cattle consumes them, as well.
Then, that night, Curious George plans ways to prevent the cows from partaking of wildflowers. As Curious George draws a diagram, the Man with the Yellow Hat asks if the Renkins are putting up a wall across their cow pasture, which gives Curious George an idea to construct a wall, but by the time which he arrives the next morning, half of the wildflowers are gone.
And then, Curious George constructs a wall by roping newspapers to a clothesline, which keeps away Jumpy Squirrel, but not Leslie and the Cows, so now Curious George seeks something stronger than newspaper print, such as wood, but Jumpy Squirrel climbs beneath the new wooden fence, which makes it non-squirrel-proof.
But when Jumpy Squirrel tosses an acorn, which hits Curious George on the temple, this gives Curious George the idea that stones are tough, and so the next morning, Curious George transports stones and rocks toward the wildflower patch, causing a cart to chase Oscar the Pig from the barnyard, as Curious George creates several attempts to build a stone wall, with all except one wildflower plant eradicated from the patch, which he covers by staggering stones, and covering his new wall with a slate slab.
So, the next day, when Curious George brings the Man with the Yellow Hat to see the flowers which he rescues, the Man with the Yellow Hat explains that dandelions have changed from yellow flowers to seeds, but will this satisfy Curious George's attempt to "Keep Out Cows?"
-----
Next, in the City, at Museum of Science, Curious George discovers new things, by looking at the dinosaur exhibit through a magnifying glass, when Professor Wiseman appears to show Curious George her newest exhibit, making it Museum of Science's third dinosaur.
Now, outside, Charkie the black Cocker Spaniel intercepts Curious George's magnifying glass, causing Curious George to chase her, and to trip over a mound, inside which Curious George discovers a bone, which Charkie intercepts once she returns with the magnifying glass.
Well, Curious George manages to track down Charkie and the bone and returns to Museum of Science with bone, figuring that it belongs to a dinosaur, but all three dinosaurs seem to have all of their bones, and so Curious George returns to Apartment Building 7, to award Charkie with Hundley the Doorman's Dachshund's treats, for her to release the bone, which she again intercepts until he manages to retrive it.
Then Curious George carries the bone upstairs to sneak beneath the table to size up the bone with the Man with the Yellow Hat's leg, but the Man with the Yellow Hat doesn't seem to match with this bone, so Curious George enters the Pet Store, to size up the bone with various animals, but to no avail, and so Curious George enters the Zoo, to discover the giraffe too tall, while the meerkats won't cooperate, while the lions are too big and vicious, and so Curious George carries the bone to Bijou Theater to observe a dragon upon its marquis, and from there it's up to Curious George's imagination to bewilder him.
But, back at the apartment, when the Man with the Yellow Hat drops jigsaw puzzle pieces, and Curious George discovers them in his bowl of cereal but doesn't think that the pieces match anything, the Man with the Yellow Hat tells Curious George that you can't tell what the elephant in the puzzle looks like by one piece.
And so, Curious George takes the bone into the streets, where Charkie again intercepts the bone and runs to Endless Park to bury the bone, so Curious George must excavate, where he discovers another identical bone and digs for more, to discover several identical ones, thinking that they belong to a dinosaur, but the bones all appear alike.
So, when Professor Wiseman arrives to the site of Curious George's excavation, along with Charkie, Betsy and Steve, Betsy explains that the bones are Charkie's missing toys, and Steve explains that they have just purchased a new toy, before the Park Patrolman orders Curious George to refill the hole. But then, what really lies beneath Endless Park under "Curious George and the Missing Piece?"
