Henry Alden and his little brother, Benny Alden and sisters, Jessie Alden and Violet Alden were Boxcar Children. They used to live alone in a boxcar (it looks like a mobile home) which they found in the woods when their parents died; at the time they were very young. After their grandfather took many years to find them, they finally have a home to live with their grandfather.
One day, a daughter of their grandfather's friend who has a champion dog, Sunny, invited them to a dog show at Greenfield. When they went to the dog show, the Boxcar Children met all kinds of dogs, from a spotted Dalmation to a big, hairy sheepdog. After the first day of the dog show, some strange things happened such as a man came out running and yelling that his beautiful dog had been shaved into ragged strips, polka-dot cat ran into the dog show and all dogs chased after the cat and disturbed the show for a while.
Next day somebody took away Sunny, the champion dog. This upset the owner, Caryn, the daughter of their grandfather's friend.
The Boxcar Children were eager to help Caryn and tried to find out the mystery that happened during two days in the show. They found some suspicious suspects: the first one was the woman whom they assisted in exercising her dog for preparing the dog show; the second one was Mr. Burger who was very jealous of Caryn for her dog always won the championship; the third one was a man who tried to open one of dog's cage and always hovered around the place.
Before they tried to figure it out, they needed to take their dog, Watch, to visit Dr. Scott for appointment. At the same time, Benny found...