Plot summary
Traveling through deep space, the Enterprise stops to investigate an odd phenomenon of phantom sensor readings. Meanwhile, ship's counselor Deanna Troi experiences pain and loses consciousness as her empathic abilities suddenly cease to work.
The crew discovers they cannot resume course, as the Enterprise is caught up in a group of two-dimensional lifeforms.
Without her powers, Troi suffers a tremendous sense of loss, and goes through several classic psychological stages, including denial, fear and anger. Ultimately, despite the reassurances of her friends, she resigns as ship's counselor, believing that without her empathic abilities she cannot perform her duties.
Commander Data and Commander Riker determine that the two-dimensional creatures are heading for a cosmic string, with the Enterprise in tow, and that once they reach the string the ship will be torn apart. Realizing that Troi's loss and the ship's predicament are somehow linked, Captain Picard pleads with her to try and communicate with the strange creatures.
After attempting to warn the creatures of the danger posed by the cosmic string, Troi posits that they are seeking out the cosmic string in much the way a moth is drawn to a flame. Working from this hypothesis, Data simulates the vibration of a cosmic string, using the deflector dish at a position well behind the Enterprise. The simulations eventually cause the creatures to briefly reverse their course, breaking their momentum long enough to allow the Enterprise to break free.
Freed from the two-dimensional creatures' influence, Troi's empathic ability is restored. She discovers that her powers were never lost, but were instead overwhelmed by the two-dimensional creatures' strong emotions. Troi returns to her old job with a renewed confidence.
Credits
Adapted from Wikipedia contributors, The Loss. Paragraphs and formatting adjusted; illustrations, reference markers, block quotations and non-story material omitted.