You transport to a prehistoric time. There is no much to do here but the environment is maze-like and, unlike in the original version of the game, the Mapping Chip doesn't work here. The rule of thumb is that whenever you are in a junction or crossroad, the correct turn is the one which corresponds neatly to a direction (N, W, S, E) on your compass.
The AI will warn you whenever you are near hazards. If you are careless enough you can fall off cliffs. You have 2 hours to complete this mission before your energy is depleted, which is more than enough.
Turn to the N and go forward; after 4 times you will be at a junction with turns to the W and the E. Turn W to your left and walk forward (3 times) until you reach a wall. Turn S to your left and walk up (4 times) to the wall. When you turn to your right you will see a cave (and also hear a "click" as the flashlight is swtched on). Enter it and zoom into the device; click on the release switch to throw the circuit breaker and reinstate power to the Bridge (10).
Exit the cave and follow the way back to the junction; you will be facing to the E turn. Follow it and your are on a cliff. The S way to your right leads to the bridge (The way to your left leads to a dinosaur cave; feel free to go there and see the eggs, but if you walk towards them, their mother will kill you). Follow the way to the ring structure and operate the nearby device to activate the bridge (10).
Traverse the bridge and use the JOURNEYMAN KEY on the figure on the cliff. Take the HISTORICAL LOG disc (5) and select the Pegasus Chip from your inventory and click RECALL to transport out (10).
You are back in TSA but the universe has changed. You receive a message from an alternate history Baldwin. Exit the Pegasus and follow the catwalk back to the turbolift to the Ready Room and then traverse the long corridor to the Command Center. Once more, sit on the seat and use the HISTORICAL LOG disc on the console (5).
Browse the four entries in the list and watch the unaltered and altered videos for each of the different events: Mars (2+2), NORAD (2+2), Related (2+2) and WSC (2+2). You find out that someone altered history in order to make the aliens cancel their arrival. After you have watched all the videos, you receive another message fro alternate-Baldwin who finds out what happened but can't risk allowing you to change history. He sends the 2 sentry robots 1 and 2 in front of the Command Center door. If they see you, it's game over. However the AI overrides and links you to the TSA central computer. Simply click on the Main Entrance to redirect the robots there and zoom out. You are now free to go to the Ready Room (5) and begin your mission.
Return to the Pegasus and enter it. Baldwin makes one final attempt to stop you, but once more is overriden by the AI. After calibration, you can begin your mission with one of three destinations: NORAD, Morimoto Colony or WSC.