Hundreds of years from now, surviving humans discover how to send consciousness back through time, into people of the 21st century, while attempting to change the path of humanity.
In a future world devastated by disease, a convict is sent back in time to gather information about the man-made virus that wiped out most of the human population on the planet.
During an experiment into time travel, a scientist finds himself trapped in the past, "leaping" into the lives of different people, sorting out their problems and changing history in hopes of getting back to his own life in the present.