Worf finds he is the only one who notices reality changing — and his sanity ebbing — after he returns from a Klingon bat'leth competition.

Wil Wheaton (Lt. Wesley Crusher)
Patti Yasutake (Nurse Alyssa Ogawa)
Mark Bramhall (Gul Nador)

• Alexander is said to be visiting Worf's parents on Earth.
  
• The Enterprise returns to the Argus Array, first seen in the episode "The Nth Degree". In one reality, the Cardassians reprogrammed it to spy on starship development sites: Deep Space 5, Starbase 47, Iadara Colony, and Utopia Planitia.
  
• During the various realities Worf and Troi are married; Wesley Crusher appears as a Lieutenant on the Enterprise; Alyssa Ogawa appears as Doctor Ogawa; Geordi dies in a Bajoran attack while a Cardassian in Starfleet uniform operates the helm.
  
• The shifts are triggered by Geordi's VISOR.
  
• At the end of the episode, Worf invites Troi to stay for dinner and they celebrate his birthday with champagne. This marks the beginning of their short "relationship."