Henry Huggins is in the third grade and lives on Klickitat Street, and he thinks his life is boring. One day, after swimming at the YMCA, Henry finds a stray dog. The dog is skinny and hungrily looks at Henry’s ice cream cone. Henry feeds the dog his cone and shoos him away, but the dog follows him. Seeing that the dog doesn’t have a collar, Henry decides he wants to adopt him. He names the scrawny dog Ribsy and finds a telephone to call his mother. At first, Henry’s mother is worried that he is in trouble, but Henry tells her about finding Ribsy and begs her to bring him home. Mrs. Huggins is uncertain, but, after Henry pleads, she agrees and tells him that he must bring the dog home on the bus. Before he hangs up, Mrs. Huggins hears Ribsy scratching, and Henry tells her that he has fleas.

When Henry tries to board the bus with Ribsy, the bus driver tells him dogs aren’t allowed on the bus and must be transported inside a box. Henry quickly runs to the drugstore and asks for a large box. Ribsy climbs inside, and Henry carries the heavy box back to the bus stop.