As Fievel enjoys playing in a friend's tree house, he hoped to get one for his birthday, so papa's new violin is a wretched disappointment. After it gets broken with Tiger's accidental help, mama works on papa to make him see a concert instrument is his dream, a tree house the kids. As the only suitable wood, from the diablo tree, must be brought over by train, papa sets out, but Fievel didn't know so he takes Tiger, whom they try to pass off for a dig like the suspicious conductor, the hobo way...
—KGF Vissers