So the idea is loosely based on the ideas behind John Carter, about quite an ordinary girl who when she dreams dreams herself a woman of on another planet, and soon the boundary between what is real and what is dream blurs and she is no longer sure who dreams who the mousy girl dreaming of the alien princess, or the princess dreaming of the plain girl in the hectic world of steel and glass.
In the real world this girl is mousy, unassuming, small and brittle, noone of consequence and noone anyone takes notice of.
In the dreaming world she lives in a luxurious palace as a sexual slave, utterly content with her role and relishing each new possibility to fuck her prince who dearly loves her, even though he can be rough with her at times.
After moving between the two worlds the mousy girl slowly starts to assert herself, take charge of her sexual destiny on Earth and become something of beauty and power, and the princess-slave grows more and more submissive, happier in her position than ever before.
[Filled. Thanks to all who expressed interest.