Jack and Annie find the magic tree house and learn they must travel to the White House to meet Abraham Lincoln, the president of the United States. When they arrive at the White House, they are unable to meet with the busy president. So they use a potion that transports them to a desert, where they help a boy named Sam by offering to do his chores, though they do not know how. In the end, Sam does the chores himself and they return to his home.