There a few I have in mind, if any of them appeal to you, let me know.
1. Holidaying on a foreign country, I decide to visit a bdsm master or mistress. During our session, they decide to keep me, as only they and I know that I'm here, keeping me as their slavegirl, bondage maid, model, or pet.
2. While holidaying, I help a prostitute to escape her life,giving her money for a trip home. Her pimp finds out, and has me kidnapped to take her place.
3. Travelling with my boyfriend, we try out a fantasy, with me as a streetwalker that he picks up, only I'm mistaken for a real one and snatched from the streets by a well known and wealthy pimp, who has me altered to look more like one of his girls and forced to work for him or her.