The Enterprise's computer system falls prey to a mysterious electronic "virus" which programs the ship to self destruct.
The Starship Enterprise enters the Neutral Zone in response to a desperate plea for aid from the U.S.S. Yamato, which has been crippled by a series of dangerous, inexplicable malfunctions on its voyage to the homeland of the Iconians, an extinct civilization.
When the U.S.S. Yamato's captain tries to explain his mission to Picard, the transmission breaks up and the Yamato suddenly explodes. Investigating the incident, Picard learns that a mysterious probe was launched at the starship several days earlier, emitting a burst of energy at the ship. En route to Iconia to retrace the Yamato's course, the U.S.S. Enterprise experiences system failures similar to those the doomed vessel faced prior to its destruction. Geordi informs Picard that the probe rewrote the U.S.S. Yamato software, causing its disintegration, and that the U.S.S. Enterprise computer was infected when it downloaded the U.S.S. Yamato log, prior to the ship's explosion.
In an effort to save the U.S.S. Enterprise, Picard and an away team beam down to Iconia. At the same time, a Romulan vessel orders the U.S.S. Enterprise to leave the Neutral Zone and begins firing photon torpedoes at the ship, whose malfunctioning shields cannot be raised. Fortunately, the Romulan weapons suddenly disarm - it becomes clear that their ship is also "infected." When Riker is finally able to activate the Enterprise's shields, he orders that they be kept up to deflect another Romulan attack - even though it will prevent the away team from being beamed back aboard.
Meanwhile, the away team discovers a gateway on Iconia which allows for time travel. When the power source which has been activating the probes tries to rewrite Data's software, Worf saves him by carrying him through the gateway in which an image of the U.S.S. Enterprise has appeared. Back on the starship, Data's self-correcting mechanism begins overriding the foreign program, reminding Geordi that the U.S.S. Enterprise computers have the same capability. After Picard destroys the power source on Iconia to keep it out of Romulan hands, he beams safely back to the Enterprise.
By Dark Materia on 13 Dec 2002 20:18:52 This was easily the best TNG show to date when it aired. From the point when the Yamato explodes (and what a bang that was) the show is tense and filled with mystery and danger. The Romulans are always great to see, and the Iconians are fascinating. There are some great comedy lines from Data and Picard. One of my favourite early TNG episodes.