Trefry began her career as a screenwriter with original film projects. Two of her unproduced feature screenplays,
Pure O and
Revolver, were included on the annual
Black List of notable unproduced screenplays in Hollywood. and later became a
co-executive producer on the series. In addition to her work on television, Trefry co-wrote the screenplay for the horror film
Fear Street Part Three: 1666 (2021), part of Netflix's
Fear Street film trilogy. Trefry also wrote and directed
short films. Her short film
How to Be Alone (2019) premiered at
South by Southwest. She also co-wrote the short film
Souls of Totality (2018). In 2023, Trefry wrote
Stranger Things: The First Shadow, a theatrical prequel to the television series. The stage play premiered in
London’s
West End and was developed in collaboration with the creators of
Stranger Things. == Filmography ==