As a history teacher, Chrysta Williams should have been thrilled for the chance to travel to the past. After all, it's the perfect opportunity to see Earth before the impact. But once she learns about her father's research, she's certain she may be putting all that beauty in jeopardy. Her father had experimented with stones from the same meteor that devastated Earth and figured out how to reactivate them. He also discovered the stones contained celestial properties that produced enormous power. Enough to travel anywhere through time. Since their salvation lies in the past, this breakthrough gave them hope for their future. With their life-support systems failing, and Earth far from healed, Chrysta has no choice but to travel back in time. It doesn't take long for her to realize that she barely has any control over the immense energy her stone generates. Now Chrysta not only must save her world, but also protect the innocent citizens of the past from the same deadly cosmic forces that had so viciously massacred the future.