The Terran Cycle4 books in series
Intrinsic Publisher's Summary
Kalian Gaines has a secret; he just doesn't know it yet. He looks like us, he lives like us...but he is not one of us.
Kalian knows nothing outside of his mundane life teaching history on 30th-century Earth, until a day like any other triggers a series of events that will tie his fate to that of humanity.
A human handprint, embedded into a rock with alien script, is discovered on a moon that mankind has never set foot on. This discovery holds a secret, which will sweep Kalian into the heart of a conspiracy that has corrupted the galaxy for 200,000 years.