Living History - John L. Purdy - Bog

Living History's protagonists, Mia and Hugh, encounter a space vehicle that crashed in the mountains of the Pacific Northwest in the ninth century C.E. The problem is: they cannot remember this, when they find themselves in 9,000 B.C.E., where their long journey begins. Aimed at a short time before the crash to prevent the ship from crashing, their time travel is an experimental "shot in the dark," but the experiment fails.
However, as they struggle to stay alive, they are not without resources: the beings, who come to be called "cousins," have implanted Nano technology in them to maintain their bodies and minds, but also an ability for to communicate without speech. In Mia, they provide a store of limited information, which includes a database of human languages but also information on the location of six research stations from which generations of cousins have monitored human evolution for millennia with periodic expeditions.
These stations frame the plot as they learn how to use them while they travel the world interacting with people and cultures through deep time, and come to devise a plan to use their unique situation to prepare for the day when they return to current times to set in motion a series of events to transform radically the course of human history, sending humankind on a quest to recapture its lost kinship with the world that surrounds them.
The only obstacle to their plan, besides the obvious hazards of such a long lifespan, is a branch species of humanity that has preyed upon humans for all time, and who have grown in numbers to threaten the very existence for all; blending into the human race in its long migration through time, they have become virtually invisible and wield great power. Mia and Hugh must counter the Kapalna's growing interest in them in a final sprint to today, and a great awakening.