It's the US versus the world, minus neutral US allies.
The US navy got hit hard by a sneak attack in the opening moments, and has been struggling to cope against superior numbers ever since.
The US is struggling, but "Fortress America" appears less safe every month. The Western hemisphere is either neutral, US allied (by coersion) or US occupied, but much of Euroasia is gathering for the ultimate naval showdown that will decide the war. The US navy at its height would have been able to stand up to the threat, but the number of ships lost makes each new ship catching up to the pre-war strenght.
The ultimate showdown commences at extreme ranges, and the outcome is constantly in doubt.
Suddenly, tragedy! A new type of stealth mine from Russia just sunk a key US mega carrier, and the balance is slowly turning! Will the hoards of Eurasia rule the seas surrounding fortress America?
But low and behold, out of the night comes the British navy! The British government had been making sounds of allying against the US, but no one knew the ultimate outcome of any negotiations.
Which become obvious, as the British fleet suddenly attacks the Eurasian armada at its most vulnerable! The battle is stabilized, and the combined might of the US and British navy ruin the enemy force. No significant Eurasian naval force remains on the seas, and the Anglo-American alliance runs rampant, destroying enemy shipyards before new vessels can emerge. The American industrial base keeps making new ships, while the Eurasian force is reduced to sneak attacks by stealth vessels. The war eventually ends, and a new Cold War begins. The Eurasian navy rebuilds, but no longer will it have the chance to surprise the allied forces with a sneak attack.
And now the historical debt from WW2 has been repaid, and then some. For the outcome of that great battle was shaped by Her Majesty's Navy.