Jack Jacobs and the Doomsday Time Machine

In this futuristic science-fiction time travel puzzler, Jack Jacobs and his organic supercomputer, Jennifer, have been gone from Earth for sixteen years in their custom-designed spaceship secretly fitted with a device that facilitates moving back and forth through the space-time continuum at incredible speeds. Now they are finally arriving back on Earth and expecting it to be the year 2199, but strangely they find themselves not in the year 2199, but in the year 2099, exactly one-hundred years into the past. After some detailed analysis of the changes occurring to the space-time gravity field lines, they soon discover that an unimaginable anomaly is causing Earth and its history to go back in time. They quickly discover they must now jump inside their ship's time warp field each time the anomaly occurs just to keep from going back in time themselves and possibly ceasing to exist. But they soon find that this is only a temporary fix, as time dilations start to occur inside their own time tunnel. Their new investigative adventure suddenly becomes a matter of life and death as they continually struggle to calculate a change in their ship's own time warp field drive. In their quest to come up with an answer for how to overcome these strange dilations, they soon find themselves in a domain of time and space where no one has ever been before…