Morgan le Fay has promised to make Jack and Annie masters of the tree house if
they can solve four riddles. In Ghost Town at Sundown, the Magic Tree
House whisks Jack and Annie back to a ghost town in the Wild West of the 1880s.
There, they meet a mustang herder named Slim as they search for the answer to
the second riddle.
Out of the blue
my lonely voice
calls out to you
what am I?Am I?
The answer is ECHO.
- They tried to save a mustang from rustlers.
- Slim's horse is Dusty