The U.S.S. Enterprise locates the U.S.S. Brattain, a science vessel which has been adrift for several days, only to discover that the entire crew, with the exception of the ship's Betazoid counselor, is dead. Troi tries to communicate with the survivor, but can deduce no information that unsheathes the mystery that took place onboard the frigate. After performing autopsies on the crew members, Dr. Crusher concludes that the 34 men and women killed each other. As Troi is being tormented by strange nightmares, Geordi finds that while there is nothing wrong with the Brattain's engines, he is unable to activate them.
While Geordi tries to rig the Brattain to the U.S.S. Enterprise to be towed, members of the crew begin exhibiting signs of increased irritability and paranoia. Troi and Beverly approach Picard to warn him that whatever happened aboard the Brattain may be starting aboard the U.S.S. Enterprise, and recommend leaving the area as soon as possible. Picard agrees, but when they try to leave, the engines shut down — just as they had on the Brattain.
An unaffected Data surmises that the U.S.S. Enterprise has become trapped in a Tyken's Rift, a massive rupture in space that is draining the ship's energy. Data points out that the ship can create an explosion to escape the rift as Captain Tyken did years before. But Picard, Riker and the rest of the crew are beginning to lose their grip on reality. A shaky Beverly approaches Picard with results of her experiments on the Brattain victims and tells him they went insane due to dream deprivation. She then points out that all the starship crew members but Troi are not dreaming, and will go insane if they do not depart the rift soon.
Data works with an increasingly incapacitated Geordi to create the explosion necessary to free the U.S.S. Enterprise from the rift. The plan fails, however, and Data informs Picard that they cannot try again. Soon afterward, Troi follows a distraught Worf to his quarters just in time to stop the Klingon from committing suicide.
Working with her catatonic patient, Troi discovers that he is experiencing the same images that she sees in her nightmares. This convinces her that they are actually in an attempt at communication. Data confirms that another ship could be trapped on the other side of the rift, and that if they could somehow be told to release a gas into space, the U.S.S. Enterprise could create an explosion to free them both. Troi attempts to reach them in a dream, while the crew releases hydrogen to combine with the other gas and create an explosion. As the last of the hydrogen is expelled, they fear they may be stuck for good, but Troi's efforts to reach the ship on the other side of the rift prove successful when at the last second, a massive explosion frees the U.S.S. Enterprise.