What happened that resulted in Dana being sent back home to her own time?

As Dana
Franklin travels through the past, she is sent back to her own time, 1976, when her own life is
in danger. 

In 's novel, ,  an African American woman
named Dana, suddenly finds herself, after a feeling of nausea, not in her home in 1976, but in
the pre-Civil War South. Dana saves a young white boy, Rufus Weylin, from...