SEASON 5, EPISODE 509 - Melinda discovers Julia, the girl who was living in the hospital dying from leukemia, hiding in Aiden's closet, now a ghost. Suspicious of her, Melinda demands that Julia leave and she can help her crossover. But Julia refuses, only wanting to talk to Aiden. She threatens Melinda fearfully with "You don't know who you're dealing with." Melinda and Jim talk to Julia's parents, to find out more about her.