Almost identical to an episode of 'Big Valley' **SPOILERS**
In that episode, Victoria and Audra Barkley are staying at a hotel during the annual cattle action. Audra disappears within hours of their arrival, while her mother is napping. Her room is empty, luggage is gone, hotel employees keep insisting Victoria arrived alone. It turned out that Audra got sick, sent for a doctor, who diagnosed anthrax. Not wishing to alarm the cattle buyers, they shut Audra in the basement.