The year is 2425. Ever since an asteroid burst through our atmosphere, carrying with it a strange germ, nature has retaken the earth. Humanity's population, which peaked in 2044 at nine and a half billion, now numbers mere millions. No one died, other than normally. But almost no one was born, either.
Meanwhile, in the present day, Thomas Reeve and his cousin Kylie create a device which they hope will allow them to communicate with the future - a once-in-a-lifetime chance to discover what the world will be like more than four hundred years from now.
But their Time Tablet malfunctions, sucking Thomas and Kylie through a portal and into the year 2425 - and they have only 24 hours to return home, and save the future of humanity...