Dorothy and friends are looking for a replacement emerald for Ozma's magic wand when they are captured by ZOG, a sea monster, and taken to his under water kingdom. The sea fairies help them escape, but when MERA the sea fairy is captured during the rescue, Dorothy sacrifices the emerald to save her new friend.

Wilhelmina steals Ozma's "copy cat" and uses it to make clones of herself and storm the Emerald Castle, demanding the ruby slippers. Dorothy and friends are outnumbered! Dorothy to combat all the Wilhelminas, Dorothy makes a fake pair of ruby slippers and lures them to the Truth Fountain.