Three warriors travel back in time to thwart alien invasion. They face the powerful Sentinel. In 2140, military rushes to help survivors post-alien attack, facing heavy losses. Forty years later, Earth refugees on the moon plan a mission led by the president to save survivors and reclaim Earth. Three skilled soldiers, Robin, Jared, and Damon, are chosen. Damon is found in a bar at the moon’s lower level. Doctor explains the mission: rescue survivors, seek human resistance help to defeat the Sentinel. Initially hesitant, Robin sees a simulation of failure but is persuaded by Jared.