Nibiru: Age of Secrets is a 2005 adventure game developed by Future Games and published by The Adventure Company.
The game features around 80 locations, 5 chapters to play in, 3D character animations, 35 NPC characters, over 50 pages of dialogues, atmospheric visual effects and scenic music.
During the construction of a new highway bypass, workers discover an entrance to an old tunnel. After they enter the tunnel, they find out that it was probably a German tunnel intentionally backfilled at the end of World War II. They contact an employee of the Western Bohemian Museum who then informs the superior body in Prague about their findings. The news about the discovery is published by the regional press the next day and there is tremendous buzz in the archeology community of the new find.
Martin Holan, a linguistics and archeology student is contacted by his uncle to examine the mysterious World War II tunnel. A friend of Martin’s uncle is supposed to meet Martin upon his arrival to brief him on the mysterious discovery; however, when he arrives in Prague he discovers that she has been brutally murdered.
And the Adventure Begins…
Source: Wikipedia, "Nibiru: Age of Secrets", available under the CC-BY-SA License.