The Journeyman Project

Claiming to be the first ever photorealistic game, The Journeyman Project takes us to the far future, to the year 2318. Humanity is on the verge on signing an historic peace treaty with an alien civilisation called the Symbiotry. However, it seems someone is altering history and meddling with the timeline. You are a member of the team assigned to guard it, and now you must use it to travel back through time and unravel the mystery and stop whoever is behind it.