The Enterprise becomes trapped in a "hole in space", where the crew encounter strange spatial phenomena and crewless ships materialising in and out of existence. The crew suspect they are akin to lab rats.
Air Date: 11/28/88
Director: Winrich Kolbe
A terrific episode that shows off the quality of what this series would be capable of in the coming years. Plenty of thought-provoking dialogue with an interesting mystery. I would have loved to see Nagilum show up again in a later season.