Penny Northern (played by Gillian Barber) was a repeater and member of the MUFON (Mutual UFO Network) group.
Agent Dana Scully met Northern at Betsy Hagopian's house in 1995 while conducting a murder investigation in Allentown, Pennsylvania. Scully found her name found among the documents related to the victim. Northern recognized Scully along with the other MUFON women who claimed she was "one of them," an abductee. Northern informed Scully about the abduction's details and about Hagopian who was dying of cancer in a nearby hospital. She also underlined the fact that all women abductees were doomed because of the procedures performed on them. (TXF: "Nisei")
Over the next year, Northern was examined for infertility at Center for Reproductive Medicine in Pennsylvania. Her health got worse, and was admitted to the Allentown-Bethlehem Medical Center under the care of Kevin Scanlon. Diagnosed with cancer, she would see the others in the group succumb to their cancers and be the only one left. She then met Scully again in 1997 and informed her of Scanlon. She visited Scully repeatedly as Scully began chemotherapy treatment with Scanlon as well. During, she recalled she had been allowed by Scully's side after the abduction's procedures, surprised by this attitude, claiming that human compassion was unusual on the abductors' part. Eventually, Northern became worse and died while Scully was visiting. (TXF: "Memento Mori")