In Curse Of Strahd, Muriel was introduced to The Pack, who were frantically searching for a missing girl named Arabelle. When they found that she had been kidnapped by Bluto Krogarov, Muriel accompanied the pack, and with her speed and bravery was able to save Arabelle from the Gigant Tayatshkala hiding below in Lake Zarovich.
After this, she took a day to recover from the beast's poison before planning her next scouting mission on Lysaga Verboczy. She requested that Atlas Atruvian use his sending magic to contact her, and relay the issue to the Keepers of the Feather in case of emergency. As she flew closer to learn of Baba Lysaga's secrets, she was found and captured. The witch bled Muriel from the neck while keeping her alive, intending to use her blood as a ritual during the full moon. Her body was completely exsanguinated and kept in Baba Lysaga's Creeping Hut.
Atlas contacted Muriel and learned of her plight, and The Pack rode to rescue her. Their approach to the hut alerted Lysaga, and the ensuing fight was disastrous. Shakti of the Wildhunt entered to destroy the hut was immediately assaulted upon her entry, and was forced to attack using a wave of thunder magic. The concussive force blew apart the room and burst the already-weakened Muriel on impact.
Muriel was later fed to Baba Lysaga's Goats, and no trace of her was seen again.