Dashenka & I are looking for another female partner for the idea below. If you're interested, please reply here in the thread.
The story is set in the modern world, and involves twin sisters who have been having recurring dreams, of both of them being loving, devoted wives to a brave robber-turned-chieftain in an ancient desert kingdom. After several months of waking up to orgasmic delight coursing through their bodies in the morning, the two sisters share the dream with each other, and are astounded to find they've both been going through it. A secret trip to a shady astrologist informs them that their dream is nothing but memories of a past life. And it's haunting their sleep for a reason, as though they had to let go of something then and it is calling them back.
The next night, they both dream a different dream - they see themselves and their husband being chased by a group of angry evil men with sharp swords. The dream ended with them jumping off a cliff into the sea, but not before the husband kissed both of them, saying, "My greatest two jewels are with me now, and my greatest treasure is our unending, undying love."
They realize that perhaps they had to let go of some kind of treasure in their past life, and it is now calling out to them, like the astrologer had told. Another trip to her den reveals the only way they can unravel the mystery of the dream - find their husband from their past life. Surely he must be reborn as they are. The astrologer adds, "For the secret to be revealed to you, you must be how you were back then. Love each other as strongly as you did back then. And the dreams will lead you to your goal."
The next day, a guy moves in to the house next to theirs.
PS: The story would involve MFF sex almost throughout.