The rain dragon rescue

As Ben and Pearl try to convince a dragon to return Buttonville citizens their things, which he stole, an emergency call from the Imaginary World comes in warning that the rain dragon has been injured. Dr. Woo is out, and Mr. Tabby is unavailable--it may be that Ben and Pearl will finally get to go to the Imaginary World and see where all Dr. Woo's strange creatures come from.