When starship sensors detect a strange pattern of images in the U.S.S. Enterprise's path, the crew stops to investigate. Unable to pinpoint the source, they attempt to resume their course, to the shocking realization that they are being pulled by an unknown force — a force they are unable to break away from. Worried, Picard calls an emergency staff meeting and asks Troi if she senses a life form. The counselor suddenly realizes that she is unable to sense anything from the force or from anyone else in the room. Her empathetic powers have failed.
After examining Troi, Dr. Crusher tries to prepare her for the fact that her powers may be lost for good. Troi grows impatient, telling her she only wants to get back to work. Later, Deanna begins to panic when she attempts to counsel a patient without her empathetic abilities. When Beverly is unable to offer any immediate hope, Troi lashes out at her. Meanwhile, Data and Geordi discover that the force that is pulling the U.S.S. Enterprise is a cluster of two-dimensional lifeforms.
Unconfident in her ability to perform her job without her powers, Troi resigns, much to Riker and Picard's dismay. Later, Guinan spots her in Ten Forward, and tells Troi how her experiences as a bartender make her the ideal candidate to take over the counselor's job. Deanna immediately sees that Guinan is joking, and suddenly realizes that while she may be without her Betazoid powers, her human instincts are still intact. Back on the Bridge, Data and Riker discover that the creatures are heading toward a cosmic string — a force similar to a black hole — and the ship, caught in their gravitational wake, is headed for certain disaster.
A desperate Picard asks Troi to use her human abilities to psychoanalyze the creatures. As she struggles to make do with her instincts, she realizes that since most life forms have an instinctive will to survive, making the creatures aware of the danger might make them change their course. Data constructs a replica of the string directly in front of the creatures as a sort of warning device, but instead of turning back, they increase their speed toward it. At that moment, Troi realizes the creatures must want to head for the string.
Data reconstructs the replica behind the creatures, and, confused, they stop momentarily, allowing the U.S.S. Enterprise to escape. They quickly resume their course and disappear inside the string. Troi's powers come rushing back to her, and she is overcome with the creatures' happiness and the realization that the string is their home. She concludes that the strength of their longing temporarily short-circuited her powers, and with renewed confidence in her human abilities, Troi happily resumes her post as ship's counselor.