Here's how I addressed the "Before and After"/"Year of Hell" kerfuffle in my
Places of Exile annotations:
Despite the order in which events were depicted onscreen, I submit that the entirety of
Voyager (and thus the 23rd/24th-century Trek universe as a whole) takes place in the timeline seen at the
end of “Year of Hell,” in which Annorax’s timeship had been wiped from existence. After all, there is no explicit mention in “Before and After” of Annorax, a timeship, or any kind of historical alterations; the only thing mentioned is that the Krenim exist and use chroniton-based torpedoes to penetrate shields.
So: “First,” in the Annorax timeline, a version of
Voyager encounters Annorax’s timeship and destroys it, resetting the timeline back to the 2170s and creating the timeline seen in TOS, TNG, DS9, and early VGR, in which Annorax never invents his timeship. Two centuries later, in May 2374 in the B&A timeline (six months after B&A), another version of
Voyager encounters the Krenim Imperium, which does not engage in rewriting history, but is aggressive in defending its territory. A Krenim ship attacks
Voyager without provocation, Janeway and Torres are killed, and the B&A version of the Year of Hell occurs. Four years later, a dying Kes jumps back to 2373 and creates the timeline seen in the series from that point on, telling Janeway of her future experiences with the Krenim. Later, in March 2374 (64 days before Janeway’s May 20 birthday), the final bridge scene of “Year of Hell” occurs:
Voyager is hailed by a different Krenim ship, one whose commander is more talkative and warns them to bypass their territory. (By arriving two months earlier, they may have encountered the Krenim before their military status had escalated to the point of firing without warning.) Janeway readily follows their advice, because she remembers Kes’s warnings about the Krenim from the end of B&A. (Why else would she so unquestioningly agree to bypass their territory, rather than negotiating for passage as she normally would?)
