After being scanned by an unidentified alien ship, the crew of the Enterprise experiences complete memory loss and struggles to discover their true identities — including new Executive Officer Keiran MacDuff, who has suddenly appeared on the bridge. Meanwhile, they become engaged in a baffling battle with the technologically-inferior Lysians.

Erich Anderson (Cmdr. Keiran MacDuff)
Michelle Forbes (Ensign Ro Laren)
Liz Vassey (Kristin)
Erick Weiss (Crewman)

• Commander MacDuff is revealed to be a Sartaaran, who have been at war with the Lysians for decades. The Sartaarans "recruit" soldiers with superior technology by erasing their memories and sending them to fight their enemies.
  
• Much of the characters' biographical information comes from the on-screen personnel files in this episode.
  
• The crew manifest incorrectly states that Beverly Crusher's rank is Lieutenant Commander (not Commander).
  
• Riker and Ro get very close in this episode!
  
• Riker plays a little bit of "The Nearness of You" on his trombone, the same song he played for Minuet in "11001001".
  
• The Lysian Command miniature is the same model as the Edo God in the first season episode "Justice". Whether or not they are implying that the Lysians are the Edo's God is unclear, but it was likely re-used for budget purposes.