Vanishers

From the turn of the 20th century, to medival England, and into the far-flung furture, Andy and Arvis must escape their pursuers, rescue their friends, and return to their own time.
Andy's friends begin to disappear and only he remembers that they ever existed. When Andy discovers another student, Arvis Voltoz, has noticed that disappearances, he follows Arvis home and begins an adventure that takes him and Arvis through time.