The reader's choices determine whether two classmates will survive after being mysteriously transported back in time to when exotic plants towered overhead and giant rat-like creatures scuttled on the ground.
The reader's choices determine whether three friends will survive after being mysteriously transported back in time to when huge insects swarmed the skies and fearsome dinosaurs ruled.
The reader's choices determine whether three friends will survive after being mysteriously transported back in time to when the climate was cold and saber-toothed cats and wooly mammoths roamed the land.
The reader's choices determine whether three friends will survive after being mysteriously transported back in time to the Neolithic Era, when humans were first learning to farm and harvest and to domesticate animals.