The series is split into four story arcs, each (greatly or loosely) based on different Oz book by L. Frank Baum: episodes 1 - 17 are based on "The Wonderful Wizard of Oz"; episodes 18 - 30 are based on "The Marvelous Land of Oz"; episodes 31 - 41 are based on "Ozma of Oz"; episodes 42 - 52 are based on "The Emerald City of Oz".
Dorothy is the only character who appears in all the episodes, including in those which are based on "The Marvelous Land of Oz" (episodes 18 - 30) - although she does not appear in the original book.
While the first and second story arcs (episodes 1 - 30) resemble the plots of the original books they are based on, the third and fourth story arcs (episodes 31 - 52) stray greatly from their original book sources.
In this adaptation the ruby slippers are magic shoes, just like the original Oz novel from 1900.