This was another exciting episode where the crew actually get hurt, including the captain who is badly scarred in a fire. It was just a shame the story couldn't have been stretched a bit longer as it was good to see the usually pristine Voyager battle-scared.
There's still moments of stupidity, such as Tuvok claiming that there is an accepted addage amongst the Federation that "The Captain is always right", but for the most part, everything comes across wholly real, and very much as though Voyager were a small town under siege by an enemy, with the once pristine hallways and decks becoming smoldering shades of dark gray and blue as power fluctuates, decks are destroyed piecemeal, and places like the mess hall become medical facilities, and a big-ass piece of debris is stuck through the bridge.
The antagonist, meanwhile, is of the Krenim race. Spoilers abounding.
It starts with the Krenim attacking and threatening Voyager for intruding into their space, while Annorax (Kurtwood Smith) commands a gigantic ship with the ability to use time travel technobabble to alter aspects of things from molecules to planets in terms of time. So he uses this to eliminate an entire species on a planet, then observes how the timeline is affected, while he and his ship is protected from these changes.
Turns out, the Krenim were involved in a hideously violent war against a superior species that it was losing. Annorax then invented this time ship and used it to wipe out this species. The timeline then sets itself so that the Krenim are suddenly a superpower... and people begin dying by the millions from a disease that this other species had cured for the Krenim generations earlier.
So he attempts more and more time incursions to mess with the timeline, and as a result, accidentally wipes out the vast majority of the Krenim nation, as well as his own wife and children. He spends 200 years constantly attempting to change time enough to set things back the way they were, or possibly better.
They take aboard Chakotay and Tom Paris, and begin working together to try to undo the damage, and set Voyager fine as it was in before the Krenim met them.
Of course, the "Magic Reset Button" must come into effect for a show like "Voyager", and everything ends up reset the way it was at "Day 1", but the difference becoming that the Krenim do not attack Voyager outright, but acknowledge them, and politely tell them to avoid their space.
The only problem I saw is that Annorax was apparently still alive, at his home, working on the time ship. But in the prior episode, it was said he had spent 200 years messing with the timeline. So was this a flashback or a continuity error? Either way, an odd change of pace from typical Voyager stupidity, and even though the Magic Reset Button came into effect, it wasn't done as stupidly as it could have been.
When the last episode ended, Paris and Chakotay were taken prisoner by a temporal ship run by a Captain Ahab-like guy, Annorax. Annorax is trying to change time in order to undo horrible things his ship did hundreds of years ago. Since one of the ship's first acts accidentally resulted in erasing all memory of Annorax's family, he's been making changes in time again and again and again--all in an attempt to undo his earlier change. But each change ends up causing more havoc and erasing various species. Clearly Annorax and his crew are playing god!
In the meantime, Voyager is a mess with a skeleton crew of only about a half dozen. Given its condition, there seems to be no way they'll ever make it back to the Delta Quadrant--let alone survive more than a few months at best.
Can all this somehow be undone? Well of course--because this went on for seven seasons! Because of this, the viewer KNOWS all this will somehow get undone--a weakness in this show. But given the action and the complexity of Annorax as a villain, it's very much worth seeing and a nice change from the usually too nice episodes of the series.