Look, it's really simple.
In another timeline, Kim finishes her AI research, single-handedly kickstarts the technological singularity, and becomes the spokeswoman for a computer god she created. Humanity becomes obsolete, gets pissed about it, and blasts Earth to oblivion. They salvage what technology they can and travel back in time to colonize an intact Earth from before the war.
However, all their machines retain the memories of the dead Earthmind. Their wormhole beacon machine, which they sent far back in time, turns into a robot which is found and studied by a past Kim. The time colonists find it just as it begins to reshape the Earth in its image, and destroy it. Kim is devastated, until she discovers that the mini-Hob is still alive and well. Kim starts uploading the fruits of her in-progress AI research into mini-Hob, hoping to restore more functionality to it and letting it properly access its memories.
Meanwhile, the time colonists assault the big city everyone lives in, aiming to eradicate humanity and take its place. Kim tries to fight them, with some success, but then gets nearly lasered in half. She is saved by the mini-Hob who got his mind together just in time. Kim has a little dream-scene, and chides her future self (whose memories were stored inside the future robots) for abandoning humanity.
Then, it gets a bit trippy. Kim, who also has the memories of future Kim, hatches from a giant blue flower, holds a speech to to the time colonists and restores their eyesight. The time colonists leave planet with some [possibly aliens or something?], along with Hob/resurrected Earthmind/Robot Quetzalcoatl. Oh, and Kim's new legs. Kim stays behind, her estranged father builds her some new limbs, and she escapes from the hospital where the army is guarding her.
Apparently this sort of thing happens quite often to her.