After a transporter malfunction aboard the Defiant, Sisko, Bashir, and Dax find themselves thrown back three hundred years into Earth's dark past without any means of getting home.

After a serious accident aboard a Bajoran shuttle, Dr. Bashir struggles to save Vedek Bareil's life while Kai Winn concludes a peace treaty with Cardassia, putting his ethics to the ultimate test. Jake and Nog reluctantly explore the differences between Human and Ferengi cultures.