Arabian Lights: The Old Tree Series (Volume 5)

In the sixth book, Arabian Lights, Mari’s father and sister, as children, discover an unusual tree. When they walk through it they find themselves in an arid desert where a great adventure awaits them. The other books in The Old Tree series are, The Land of Bizia, The Kingdom of Knon, The Mild, Mild West, Into the Night Sky, Arabian Lights, and One for All and All for One.