— Maggie to Holcombe as he dies
Very little is known about Maggie's personal life, other than she works as a prostitute and has a daughter named Sheila May. She would leave her daughter with her mother whenever she heads out to the streets for work.
Maggie is first seen being approached by a prospective client in his van. After Maggie steps into the van, she is knocked unconscious off-screen. Later, Maggie regains consciousness and finds herself in a basement, barefoot and her vision blurry. Maggie finds a door, but when she opens it, there are more doors. The last door is difficult to open and Maggie breaks her nose trying to force it open. Maggie charges at the door and is able to break it open, but she accidentally falls onto a floor filled with crushed glass, which cuts her face. She uses her jacket to crawl to the next room without cutting herself any further. Once she gets into the next room, someone communicates with Maggie through a speaker and shows her a projection of an older homeless man being brutally murdered, which horrifies her. Afterward, Maggie tries to reason with her captor by telling him that she has a daughter. The voice tells Maggie what kind of prostitute she is and tells her that she has a few hours to get out of the building she is in, which is a massive facility.
While Maggie tries to find her way out, she encounters a number of obstacles, such as gas being released into a stairwell, and a vicious Doberman chasing her. After she escapes from the Doberman, Maggie finds the remains of many people, which horrifies her. Afterward, Maggie finds an open door leading to the outside world. Already badly injured, she desperately crawls towards the exit, passing many pairs of shoes in the process, but the door shuts right in front of her. Then, gas is released, which knocks out Maggie. After regaining consciousness, she finds herself restrained on a stretcher, which is being wheeled into a room by a man wearing medical protective clothing. The man is about to vivisect her when the BAU and a SWAT team arrive and demand him to stand down. Flying into a rage, the man tries to kill Maggie anyway, but the agents shoot and mortally wound him. Afterward, Maggie demands to see the man's face. Morgan removes the dying man's surgical mask, to which Maggie tauntingly proclaims that she won. As she is taken to a hospital, Maggie asks the BAU to have someone check on her daughter.