In 1848, Ellen Craft became invisible. Ellen, a slave from Macon, Georgia, took trains and steamboats north, but the people all around couldn't see her. They saw only a white man. Ellen Craft's mother was a slave, but her father was her master, and she had skin as white as his. So she posed as a white man, while her husband William posed as her slave. Ellen vanished and became William Johnson -- an ailing gentleman seeking medical treatment in Philadelphia. The Invisible Woman is based on a true story -- one of the boldest escapes in American history. William and Ellen knew they could never have children until they were free, so they embarked on the greatest of escapes. Their incredible story riveted a nation, and it put the Fugitive Slave Act to the test, bringing attention to their plight all of the way to the White House. The ultimate irony: The invisible woman became one of the most visible symbols of freedom in nineteenth-century America.