Distressed at the loss of his family and an entire colony of his people by a hostile alien enemy, Krenim leader Annorax has mastered time manipulation and can obliterate history, making entire lifeforms and civilizations cease to have ever existed. In this way, he hopes to restore his loved ones by erasing the enemy that caused their deaths. His well-calculated plans are thwarted by the incursion of the U.S.S. Voyager. Captain Janeway and her crew come between Annorax and his plans, for which it seems he will make good on his promise to destroy the starship.

Kurtwood Smith (Annorax)
John Loprieno (Obrist)
Peter Slutsker (Krenim Commandant)
Rick Fitts (Zahl)
Deborah Levin (Ensign Lang)
Sue Henley (Ensign Brooks)

• Kes warned Voyager about the Krenim in the 3rd season episode "Before and After", but there is no mention of her warnings.
  
• Seven of Nine and Ensign Kim finish the new Astrometrics lab, a combination of Borg and Starfleet technology. It is 10 times more accurate than their existing mapping technology.
  
• Seven mentions that the Borg were present during Zefram Cochrane's launch of the U.S.S. Phoenix, a reference to Star Trek: First Contact.
  
• Neelix wears a standard Starfleet operations (yellow) uniform in this episode and in Part II.
  
• Janeway gets a haircut and loses the ponytail.
  
• Kurtwood Smith also played the Federation President in Star Trek VI: The Undiscovered Country.