Mercedes is the resident popular girl and head cheerleader at Pilgrimtown H.S., located in Pilgrimtown, Massachusetts. In actuality, she is a witch and the scion of the Dark Lord Beelzebub.
Mercedes uses her unlimited dark powers to do the usual high school pranks and hazing toward the new girl in town, Dawn (A.J. Cook). She orders a plague of insects, reanimated dead frogs in biology class, and banishing people to some kind of netherworld.
Mercedes and Dawn end up possessing half of what is known as the Devilstone amulet that together will provide ultimate power.
Mercedes sends Dawn into a medieval parallel universe. Dawn's friends, Fran (Aimee Castle), Flo (Nadia Litz) and Mary (Ioana Cristecu) must travel to the parallel dimension to find and rescue Dawn.
In the end, Dawn and her friends escape the parallel universe. However, Mercedes lands in a different universe, one that is ruled by nerds, trapped and unable to return since the portal has been destroyed.
- Lexa Doig appeared as the evil Sonya Valentine from 2012-2014 for the TV series Continuum.
- Lexa Doig appeared as Talia al Ghul in season five (2017-2019) for the TV series "Arrow".