Curious George Goes to the Hospital

George wakes up to find a box with a surprise on the desk. The surprise for George turns out to be a jigsaw puzzle (which had came in the mail the previous day before George picked it up). This puzzle had two dozen (24) pieces. George simply had to open it. He took one puzzle piece out. Thinking it's a piece of candy, he (unsuccessfully) eats a colorful puzzle piece. At first, George thought it was candy (well, maybe it was and maybe he could eat it). But whatever it was, before he knew it, he knew he swallowed it. Maybe it was candy and maybe he would be able to eat it, but still, he swallowed it either way. The Man with the Yellow Hat comes home and (at first, not knowing that George had eaten a puzzle piece before he got home) tells George that the jigsaw puzzle was a surprise for him. They both work on it. Finally, the puzzle was "finished". Well, it was "almost finished" really. However, although the puzzle might look finished, one piece was missing. Unable to find the other missing piece, they go to bed.

The next morning George has a stomachache (from swallowing the puzzle piece the night before) and is too sick to eat his breakfast. Worried, The Man (still not knowing that George had swallowed a puzzle piece; which he had been wondering all night why the last piece from their jigsaw puzzle had gone missing) calls the doctor (Dr. Baker). Dr. Baker tries to find the problem. But the doctor turns to be no help. So he recommends that George should go to the hospital.

The Man reassures George at the hospital, saying "Don't worry. You have been here when you broke your leg" (what he states is a reference to the other previous book from the Curious George classic series books; Curious George Takes a Job). George is given a barium meal from a nurse down a long hallway. Then, he goes to the x-ray room. Even though George had thought that he would get an apron like the doctor and the Man, he did not. After the x-ray is over, the x-ray picture shows the undigested puzzle piece lodged in George's stomach when he swallowed the piece the night before (after the doctor says that there must be something with the patient George which should not be). The doctor and the man look at the printed document from the x-ray and later discover the undigested puzzle piece. The man (who looks at the picture and discovers the puzzle piece) says that it was the puzzle piece missing from their jigsaw puzzle and was why he and George couldn't finish the puzzle the night before (saying, "That must be the puzzle piece which was missing from our jigsaw puzzle last night"). Now the Man finally knows that George had swallowed the puzzle piece all along (which is why George had a tummy ache all this time since morning). He had a tummy ache the whole time (which is why he didn't want to eat his breakfast that morning) and now the Man and the doctor finally noticed it when they took him to the x-ray. The doctor says that he at least knows it is clear exactly what is wrong with George. He then explains that since that's what is wrong with George, a small operation is needed to remove it. He reveals out that a tube is needed to take the puzzle piece out of George's stomach.

Later, George is admitted to the children's ward waiting room where they meet Betsy and her mother. Betsy is scared because this is her first time in a hospital. She did not want to go to the hospital. George meets a nurse named Carol, who takes him to the children's ward where George’s temperature and blood pressure are recorded, and he is given a pill and a vaccination to put him to sleep then wheeled into surgery. After surgery, George is groggy and does not want to read a new book about a dog the Man has, and goes back to sleep.

When George wakes up feeling better, he has some ice cream. As for Betsy, still not liking the hospital, she seems a little less sad. She watched George from time to time. But still, she does not smile. He meets a kid named Steve in a wheelchair (called a "go cart" in the book) with a broken leg. George is then taken to the play room where he starts doing things to break Betsy out of her sadness. He puts on a puppet show, then stands on a turntable and spins around until he flies off. The kids laugh and Betsy smiles. A play lady picks up George and returns him to the children's ward for a nap.

When George wakes up from his nap, he sees that Steve is trying to walk. With no one looking, George hops into his wheelchair and out of the room. By the time the nurse notices, George is heading down a steep ramp towards a couple of attendants pushing food carts and showing a mayor around the hospital. George crashes into the carts (and lands in the mayor's arms), spilling food (spinach, scrambled eggs, and strawberry jam) and breaking the wheelchair and the dishes (which makes the attendants complain; one about the dishes says, "YOU BROKE ALL MY DISHES!" while another as for the go cart says, "HE RUINED THE GO CART!"). The kids see the accident and the first to laugh is Betsy. This gets everyone laughing except George who cries, thinking he might be punished. Betsy consoles George, telling him this is what finally made her smile and be happy. The mayor tells George that even though he made a terrible mess, he also made the sad little Betsy happy. The adults agree George is not in trouble because he made Betsy happy, and the Man arrives to take him home. Then the adults say goodbye to George and remind him to "take care of himself".

As they are about to leave, everybody (including Betsy and Steve) waved goodbye through the windows and nurse Carol gives George a present to take home. At home George finds it to be the puzzle piece he swallowed. The man (after George unwraps the paper and unboxes the box that held the puzzle piece) sees it was the last missing piece. He is happy that the doctor and nurse had saved it for them. Then the Man (about the puzzle) says, "So now, we can finish the puzzle!". Now able to finish the puzzle, they complete the puzzle (placing the last missing piece; which is in the center of the jigsaw puzzle). In the end, the now-completed puzzle reveals to be a picture of George on the grass of the jungle with the Man's yellow hat in front of him.

• Rey, H. A. and Margaret Rey (2001). The Complete Adventures of Curious George. Houghton Mifflin Harcourt. ISBN 978-0-547-39100-7.CS1 maint: uses authors parameter (link)