This is book two of the science fiction series "The Girl with the Turtle Tattoo." The Girl with the Turtle Tattoo knows that humanity is doomed. And it's her fault. But she is determined, somehow, to find a way to save Earth-even if it means going back in time and changing history. But rather than having a fresh start, she discovers to her horror that history has a terrible momentum: ever eager to instruct, but not easily altered. And that which has been successfully prevented may yet re-emerge in a different and deadlier form. Her only hope lies in trusting an ancient device constructed by a long-extinct race of Martian intelligent reptiles. Will it be the means of her and Homo sapiens' salvation or their collective death? Only time will tell...