The story begins with a slave-master style wedding. The protagonist has chosen to completely give up her (his, if the author prefers) previous life and become a complete slave. A full submissive, her wedding vow consists of giving up her rights and her safeword. She does so happily. The wedding is somewhat of a joke in that she fully expects (quite accurately) that her master will sell her or give her to a friend within a couple months. But being a slave is her dream life, and that is part of it.
Then, she dies. I leave it to the writer to decide how, but it should be sudden. Upon dying, she finds herself in hell, where she is told that she free will is a gift from god and giving it up means she has no right to heaven. Making the punishment fit the crime, she becomes a slave in hell, too. She is passed around between various demons. Of course, she's such a submissive that being considered a slave to pass around is enjoyable. Her "punishment" is better than her wildest submissive dreams. The "demons" don't let slip that she's really in heaven for a couple weeks. They figured she'd appreciate the vicious welcome but had to tell her the truth as she needed a chance to say hi to some of her family/friends.
Then, she dies. I leave it to the writer to decide how, but it should be sudden. Upon dying, she finds herself in hell, where she is told that she free will is a gift from god and giving it up means she has no right to heaven. Making the punishment fit the crime, she becomes a slave in hell, too. She is passed around between various demons. Of course, she's such a submissive that being considered a slave to pass around is enjoyable. Her "punishment" is better than her wildest submissive dreams. The "demons" don't let slip that she's really in heaven for a couple weeks. They figured she'd appreciate the vicious welcome but had to tell her the truth as she needed a chance to say hi to some of her family/friends.