Henry, Jessie, Violet, and Benny used to live alone in a boxcar. Now they have a home with their grandfather, and they're going to a teddy bear jamboree!   When the Aldens visit Peggy and Doc Firmin's sheep farm, they're in for a teddy treats: a behind-the-scenes look at a real teddy bear workshop! Soon, the children are learning everything there is to know about teddy bears. From patching up old bears in the toy hospital to marching in the big bear parade, this vacation is stuffed full of bears! But the Aldens soon encounter an unbearable mystery: a very rare and valuable bear has disappeared from the toy hospital. Now its up to the children to track down the teddy thief!