Marnie is an 18-year-old witch that has been accepted at Witch University in Halloweentown. Marnie has to figure out who "S. Cromwell" is after she finds this silver box in one of her classes. She also finds out that you can't use magic on campus unless a teacher isn't looking then it is ok. Marnie is played by Sara Paxton who has replaced Kimberly J. Brown in "Return to Halloweentown. More on Marnie Cromwell from Return to Halloweentown later.