Dr. Crusher finds the crew disappearing from a shrinking universe.
Dr. Crusher welcomes her old mentor, Dr. Dalen Quaice, aboard the Enterprise, just as Wesley runs a warp-field experiment in engineering based on ideas from the Traveler. Soon afterward Quaice vanishes, and nobody but Beverly remembers that he ever existed.
More and more people disappear, and the rest of the crew treats each loss as normal. Eventually Beverly is alone on the ship, and she finds that the universe itself has shrunk around her into a sphere whose edge keeps closing in.
In reality she has been trapped inside a warp bubble created by Wesley's experiment. With help from the Traveler, Wesley opens a doorway, and Beverly escapes through it just before the bubble collapses.