Year of Hell, Part I & II (Star Trek: Voyager, Season 4, Episodes 8 and 9)
The crew of Voyager is negotiating with the Zahl when a Krenim ship begins attacking them. Captain Kathryn Janeway ignores the small ship; suddenly, a temporal blast hits all three ships, leaving the Zahl vaporized, Voyager severely damaged, and the Krenim ship larger and more powerful. It turns out the Krenim have a time-shifting weapon that deletes events from history that inconvenience them. Janeway has to figure out a way to use their time weapons against them while keeping her crew safe.
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