One of the most difficult and intriguing propositions that Temporal Investigations has ever investigated, the so called "Year of Hell" event sequence occurred when a Krenim scientist created a weapon system capable of erasing key events from a timeline in order to create another which would be more favourable to the users. The weapon, built into a large spacecraft dubbed a Timeship, was used by its commander Annorax in an attempt to restore the Krenim Empire to prominence after it had been defeated by an enemy race.

The case became of interest to Temporal Investigations when the Krenim encountered the USS Voyager in one of the alternate timelines. This variation on the Empire was equipped with Chronaton torpedoes, capable of penetrating Voyagers shield system. As Voyager passed through their space on its way home the Krenim launched many attacks, inflicting considerable damage on the Federation ship. Voyager replied by constructing a temporal shielding system; this also served to insulate them from further changes to the timeline caused by the Krenim Timeship.

Unfortunately for the Krenim, this introduced an unpredictable variable into Annorax's calculations. The Timeship was equipped with temporal scanning technology similar to that used by Temporal Investigations itself, and careful calculations were required in order to ensure that the weapon worked correctly. The presence of a temporally shielded Voyager threatened to provide a constant random factor into these calculations. Annorax attacked Voyager, again inflicting severe damage which ultimately caused the ship to be abandoned by the large majority of its crew.

After conducting some hasty repairs and equipping a few allies with temporal shielding, Voyager led an attack on the Timeship. The vessel was ultimately destroyed when it was rammed by Voyager, deleting the alternate timelines and restoring the situation to its original state.