What is this?!?
(please use keywords, and keep guesses under 50 characters)
Penelope the Poogle had received mysterious notes every day, all with the same cryptic message. After a week of these notes, Penelope hired an expert to figure out what the message said.
The message was as follows:
RTTDECY ZJT XZCHWEUO.
After finding out the contents of the notes, Penelope moved away to the outer reaches of Terror Mountain.
What did the message say?