My character is either witchunter or a paladin or a druid of somesort who is investigation an evil cult or a cabal. She gets captured and lands in the clutches a sorceress serving the cult (your character). Luckily for me, the sorceress intends to betray the cult for her own ends (what those ends are, is up to discussion) and she decides to use her new captive to achieve that.
Of course, she has to make sure she has her captive under control and she has to keep appearances to the rest of the cult, so she dominates and uses her as her favourite sexslave regularly. Eventually, the captive may even learn to like it and wish to remain a slave after the cult is destroyed. Or they may both plan to kill eachother after the victory.
The focus would be how the captor seeks to remain in control and captive reluctantly submits but seeks to regain control while they have to work to destroy their mutual enemy.
The setting would be fairly standard high fantasy, or perhaps more dark fantasy if you prefer. Please read my ons/offs and PM me with some details of your character and any possible ideas for plot if you are interested.