I'm a well read grad student who's bluntly honest about all things, although I try to be most honest about myself.
The Borg try to assimilate by using a tachyon wave that rips through the past: they will assimilate all those who tried to stop them before they even knew to try and stop the Borg.
They especially want to assimilate the little girl who will one day become their queen and come up with this plan.
There's some really nice touches here, including The Locutus Protocol that Admiral Janeway suggests using to stop the Borg. Or the way that Guinan helps Picard think through things so that they can, in fact, come up with a better plan.
Just really enjoyed this story. I'd read a whole series about the Borg.