Twins, one sister always locked in cell, they switch monthly based on card game

[Budman0_0]

I remember a story about twin sisters.  They move to a new town where no one knows them (as I remember it) and buy a house.  They either build or find a cell in the basement.  One of them is always kept locked in the cell naked by her sister.  Every so often (monthly as I remember) they play a card game and the looser has to spend the next month in the cell.  They have a job which they share, their coworkers never realizing there are two of them.

Is that jogging anybody?