While conducting a search for the missing medical transport U.S.S. Fleming NCC-20316 in the Hekaras Corridor, the Enterprise encounters an alien brother and sister who insist that warp-drive engines are destroying their region of space.

Michael Corbett (Dr. Rabal)
Margaret Reed (Dr. Serova)
Lee Arenberg (Daimon Prak)
Joyce Robinson (Ensign Gates)

• The Hekaras Corridor is a safe route through an area of space filled with tetryon particles, which pose a navigational hazard to warp vessels.
  
• To prove her threory (and martyr herself), Serova breaches her ship's warp core and the explosion creates a subspace rift, which makes it impossible to create a warp field.
  
• La Forge takes the warp core off-line to adjust the power conversion levels. The chief engineer of the U.S.S. Intrepid, Donald Kaplan, is competing with La Forge to increase power conversion efficiency. The Intrepid can be assumed to be the newly launched prototype (NCC-74600) of the Intrepid-class U.S.S. Voyager NCC-74656.
  
• The Federation Council imposes a speed limit of warp factor 5 during this episode, except in extreme emergencies.
  
• This episode was meant to be an environmental statement, but ended up being a little bit silly with the restrictions and ramifications, which will be forgotten within a few episodes.
  
• Later starship designs, such as the the Intrepid-class U.S.S. Voyager and the Sovereign-class U.S.S. Enterprise-E, utilize new warp designs that do not damage subspace.
  
• Spot is now a female cat, though Data referred to him as "he" in earlier episodes.