Yukikaze gets thrown in an alternate world on 7 December 1941, near Pearl Harbor. Both the IJN and USN use shipgirls in the soon-to-begin Pacific War.

Yukikaze's arrival roused Enterprise's suspicion, so the latter (along with her escorting destroyers) interrogates Yukikaze, but Yukikaze managed to escape to the Kidō Butai thanks to a storm.

Kidō Butai members are jerks, threatening Yukikaze with execution for cowardice (okay, this behavior was technically 'historically' accurate). Then again nobody can be directly involved in Pearl Harbor without looking like jerks anyway (this is also historically accurate).

Yukikaze has her memories from both our real-life timeline (as her time as an actual ship) and as a kanmusu in the Kancolle game (with her being somewhat aware of its status as a game, as seen in the prologue). The IJN and USN kanmusus only have their memories in an alternate history up to 1941 ('though we can expect the alternate events to somewhat mirror their real-life counterparts).

Naturally we get to see a lot of PTSD episodes from Yukikaze, especially after she met Hiei and Isokaze, two of the ships she was personally involved in scuttling in our real-life timeline.

On the USN side we get some feels from Enterprise and her flashbacks of Arizona, after she hurried back to port to survey the damage.

The timeline diverges from ours at three major points:
1) IJN and USN use kanmusu/shipgirls, as mentioned.

2) Yukikaze is aware of our timeline's history (and how her friends were massacred in the Pacific War), so she attempts to change history by persuading the Kidō Butai to:
a) Press on with a third wave of bombers (which they didn't do in real-life, allowing the US to quickly recover as most of their port facilities survived) to destroy fuel depots and other facilities.

b) Find the USN carriers and destroy them.

(Assuming that the kanmusus would operate on an equivalent level with their ship counterparts, the IJN would still lose even if they did a. since Japan's economy was floundering while the US was booming. Most it would do is to delay the conclusion of the war by two or three years or so, while causing further deaths than necessary.

[Especially to whichever indigenous population under the IJA's thumb]

Doing b. may make the US more inclined to sue for peace, or make them even more pissed off, I can't tell. In any case the US's industrial might will still allow them to replace the losses in well, two years or so.

Of course, kanmusus may operate differently, and the IJA in this alternate verse may be whitewashed compared to real life [not that I count on it from a Chinese author])

3) On the USN side we have Enterprise, who's tipped off earlier of a possible Japanese attack due to her encounter with Yukikaze. She still arrived late at Pearl Harbor though, because of to the storm, but she's in position to help fight off a possible third wave.