In the distant future, the remnants of humanity live out their days within bunkers underground after a dangerous virus ravaged the Earth. You are a soldier tasked with guarding one of these bunkers. One day, you wake to find that a rift in space-time has been torn open in your subterranean haven, threatening the safety of everyone within. Travel between the present and the past as you try to close this rift and discover the secrets of what really caused humanity's downfall.