Sci-fi / fantasy (time-travel) with a purpose.
"Impossible Journey is reminiscent of The Time Machine by H. G. Wells with a unique twist."-- Tami Brady (Goodreads)
Each of these historical time periods points in some way to the true answer they are seeking. But they ignore the obvious and go on blindly with their mission.
At one point, they are pulled forward unexpectedly to their future where robots serve and are forced to fight in a senseless war. Will they escape? And will they ever come to learn the true answer to the problem of sin and evil in the world?