She had signed her life away years ago.
She is a starved,beaten and abused slave her master has already got her replacement who he encourages to abuse her to ( or she get the punishment to).
They are at a party of some kind she when she hears a dom say the contract illegal,so she finds the strength to run.

She hides and escapes her master,starts a new life years later she is helping others .
But her past catches up when her old master finds her.