The Lights of Zetar

A mysterious storm has inflicted heavy – perhaps irreparable – damage on the library planetoid Memory Alpha. And it seems to have a curious affiliation with new crewmember Myra Romaine. As the Enterprise pursues the hazard, Romaine falls more under its influence, and the crew learns it is not a storm at all, but a form of life that means to survive at ANY cost.

Synopsis adapted from TVmaze (CC BY-SA 4.0)