Geordi meets the real Dr. Brahms he once "met" as a Holodeck image, who is onboard to study his engine modifications. A newborn lifeform attaches itself to the Enterprise and is draining its energy.

Whoopi Goldberg (Guinan)
Susan Gibney (Dr. Leah Brahms)
Lanei Chapman (Ensign Sariel Rager)
Jana Marie Hupp (Ensign Pavlik)
April Grace (Transporter Chief Hubbell)

• Geordi created and fell in love with the holodeck Dr. Brahms in the episode "Booby Trap".
  
• "Junior" was a computer generated animation.
  
• "Junior" was attached over Shuttlebay 3 according to the published ship schematics, but the crew said he was attached over Shuttlebay 2.
  
• This is the first episode where we see the Jeffries Tubes, used to access the ship's inner systems.