Gretchen Ross is a key character in Donnie Darko, and Donnie’s romantic interest during the events of October 1988.
She moved to Middlesex, after an incident in which her step-father tried to kill her mother. In the tangent universe, Gretchen meets Donnie after attending his school, and the two eventually become romantically involved.
Towards the end of the film, she is killed on Halloween night when Frank runs her over.
As the events throughout most of the movie took place within an alternate universe, everything that “happened”, including her death, did not actually occur.
