okay

so basically Comstock is being a butt and wants a daughter so he stole this one girl Elizabeth and made her his daughter, but now Booker has to save her

The thing is, he *TRAVELED THROUGH TIME AND SPACE* to steal the girl thanks to the weird-ass tech the Luteces came up with

aaaaaand the Luteces are like the same person, one from a male Lutece timeline and one from a female Lutece timeline

also something about Elizabeth's pinky (not sure if quite spoilerino, as it explains some stuff that's questioned during gameplay)