Conversation so far:
When did Mary Shelley write Frankenstein?
Mary Shelley remembered in 1831.
What did she have to do with Lake Geneva?
close to Lake Geneva at the village of Cologny; Percy Shelley rented a smaller building called Maison Chapuis.
what did they do while they were there?
They spent their time writing, boating on the lake, and talking late into the night.
.
What did they write while they were there?
Byron to propose that they "each write a ghost story".

Question: Did they write the ghost story?
Self-contained rewrite: Did Mary and Percy Shelley write the ghost story?