What happens when markheim goes upstairs

When Markheim went upstairs he found and encountered a strange person there who seemed to be a supernatural being of some sort.

Explanation:

"Markheim" is a story which has been written by Robert Louis Stevenson who is a Scottish author. This is one of the strongest works of this Scottish author which is a short story written in the year 1884.

The story is about a character named Markheim who has entered in a shop to buy a Christmas gift. The whole story revolves around this incident only in that shop.