Scully begins to come to terms with the fact that she has cancer, but her friends and allies begin fighting to save her life, even if it means making a deal with the devil...
Scully stands in a hospital gown next to a bare lighted wall, studying a cranial x-ray that she holds. The x-ray shows an irregularly-shaped transparent mass, between the eyes and behind the nasal cavity.
HOLY CROSS MEMORIAL HOSPITAL
Assistant Director Skinner meets with the agents in his own office, sympathetically learning of Scully's plight and agreeing - on her request - to keep the matter confidential. Scully relates to Skinner that she is eager to start investigating her cancer and Mulder informs him that, in the previous year, the agents encountered a group of female purported-abductees who reported symptoms similar to Scully, after having implants removed from the base of their own necks. According to Mulder, one of these women, Betsy Hagopian, had been undergoing treatment but has recently been uncontactable.
Mulder and Scully arrive at Betsy Hagopian's former property, only to find it is soon to go on sale. A female realtor opens the door to the agents, jumping to conclusions about their identities, and reveals that Betsy Hagopian recently passed away. After Mulder shows his FBI badge to her, the realtor reveals she is ignorant of Betsy's activities as a MUFON member. On Mulder's request, the agents are allowed inside, where Scully begins to recall having met the women. The agents discover that someone is remotely accessing a computer in the building's basement and Scully starts to call for a trace to be run.
She and Mulder arrive, at night, outside the apartment building where the hacker, Kurt Crawford, lives. The duo attempts to enter the building, Mulder heading up a fire escape at the property's rear. Kurt Crawford makes an escape attempt but is caught by the agents. Mulder notices blood running from Scully's nose but she insists that she is fine.
In Kurt Crawford's apartment, Scully cleans her nosebleed but exits to find that Mulder has released Crawford from handcuffs. Scully learns that Crawford is allegedly an innocent MUFON member who was downloading files for safekeeping, as he believes a dangerous government conspiracy is trying to cover up the files and were involved in the fates of the women. According to Crawford, virtually all the other members of the MUFON group that Scully met died from cancer in the last year, with the exception of Penny Northern, who is now hospitalized in critical condition. Mulder privately advises a reluctant Scully to not only admit that her condition was due to her own abduction but to also interview Penny Northern, as an investigator if a personal visit will be too difficult for Scully.
ALLENTOWN-BETHLEHEM MEDICAL CENTERScully visits the bed-bound Penny Northern, who startles Scully by immediately recognizing her. Penny tries to remind Scully of having met each other during Scully's abduction but Scully apologetically explains that she has no memory of that experience. When Scully declares that she came to ask Penny some questions, Penny presumes that Scully's queries were to be about Doctor Kevin Scanlon, who treated Betsy Hagopian and is now treating Penny. According to her, Doctor Scanlon is close to finding the cause of the cancers.
Receiving a call from Scully at Betsy Hagopian's house, Mulder tells her he has found evidence, in the MUFON files, that some of the group members had been treated at a nearby fertility clinic. Scully lengthily asks Mulder to help her be readmitted into hospital, so Mulder helpfully agrees. He irritably departs and heads for the medical center. Armed with a gimlet weapon, the Grey-Haired Man subsequently enters the house and executes Crawford. As the man exits, Crawford lies dead, his remains becoming a puddle of green ooze on the basement floor.
Act TwoLying in bed, Scully slowly awakens to Doctor Scanlon standing in the window light. He reminds her - referring to her medical training - that the chemotherapy and radiation will be very traumatic for her. Scully's mother arrives so the doctor leaves. Although Agent Scully tries to assure her mother that she doesn't feel ill, Mrs. Scully is outraged that her daughter didn't immediately tell her about the cancer. Agent Scully professes that she had been waiting for answers and claims she has found some clarity in the hospital, as well as a possible way to fight back. An upset Mrs. Scully urges her daughter not to keep information from her and reminds Agent Scully that she is now her mother's only daughter.
Scully begins chemotherapy and radiation during which she is comforted by Penny Northern. Mulder goes to the Center for Reproductive Medicine in Lehigh Furnace, Pennsylvania at night and attempts to run through the center's computer files. A man identical to Kurt Crawford is also there looking for data, and Mulder thinks he is dealing with the same man, not knowing about the first Crawford's execution. They manage to find information about the Lombard Research Facility, a fertility clinic at which Agent Scully's name figures in the directory. Mulder asks Assistant Director Skinner to arrange a meeting with the Cigarette-Smoking Man, but Skinner advises him to find another way, saying "you can't ask the truth of a man who trades in lies."
Act threeMulder decides to turn to The Lone Gunmen for help and they make their way to the Lombard Research Facility. Mulder sees Doctor Scanlon's name among the facility's doctors and urges Byers to run to Scully to tell her she should stop her treatment as her physician is not trustworthy. Mulder continues to explore the facility and sees light coming from one of the laboratories. Another man identical to Kurt Crawford opens the door wearing a white smock, and to Mulder's amazement, half a dozen of these men are keeping busy around the room, Kurt Crawford being part of a hybrid series, adult hybrids cloned after the same individual as the male Agrarian Drone clones Mulder had previously met in Alberta, Canada. The laboratory is filled with large tanks where maturing clones' bodies are nurtured in a greenish fluid. The Crawford hybrids reveal their intention to subvert the colonization project, saddened by the female abductees' lot who are in fact their biological mothers. One of the Crawford clones takes Mulder to a storage vault where ova from the female abductees are kept, including Scully's. Mulder takes one of the vials and walks out, just before the Grey-Haired Man's arrival, apparently warned of Mulder and the Lone Gunmen's break-in. The armed man pursues and attempts to shoot the agent through a bullet-proof glass door, but fails to do so.
Mulder runs to the hospital where Scully has already learned the news about Doctor Scanlon from Byers. Scully remains at Penny Northern's bedside all night and the woman gives up the ghost at dawn. Scully is distraught as she gives Mulder the sad news. She decides to cease her treatments and shares her struggle with Mulder who embraces and comforts her. Mulder calls Skinner to tell him Scully is coming back to work. It is then revealed that Skinner has contacted the Cigarette-Smoking Man after all and is about to make a deal in an effort to help Scully.
- A storage drawer holding Scully's harvested eggs was labelled with a card dated 10/29/94. This date should correspond to the time period of her abduction by the aliens.
- Mulder gets the password to Scully's infertility file from a snowglobe with a large, Ukrainian Easter egg. The snowglobe is a knick knack from the real Canadian town of Vegreville, Alberta.
- The title of this episode means "remember that you are mortal" in Latin. In Latin, it can also mean "Remember you will die". The phrase 'Memento Mori' also refers to a type of Victorian photography in which a recently deceased person is photographed postmortem, often with family members, dressed and posed as though in a deep sleep rather than dead. In the days of the Roman Empire, a military leader achieving great victories would be given a parade through the city of Rome where he in the end was told Memento Mori, so that he wouldn't forget his place in the world.
- A scene with Gillian Anderson (Scully) and Pat Skipper (Scully's brother, Bill Jr.) was cut due to time constraints. The scene was significant for several reasons in that Bill Jr. voices his displeasure, or rather what he believes to be his parents displeasure, about Dana choosing to be an FBI Agent instead of a doctor and that now she has paid for that decision with her cancer. He also indirectly blames Dana for Melissa's death and, finally, he mentions their other brother Charles.
- Pat would make his second 'first appearance' later in the season finale "Gethsemane".
- It was for this episode that Gillian Anderson won an Emmy for Outstanding Lead Actress in a Drama Series.
- According to media reports, Kurt Crawford is actually the name of Chris Carter's contact at the FBI whom he goes to check facts for accuracy.
This episode originally had a kiss on the lips between Mulder and Scully. In the original version, Mulder kisses her forehead, then her lips, then they hug and she walks away. The aired version just has the kiss on the head.
The date on the drawer holding Scully's ova is October 29, 1994 - a few days before she was returned to the hospital in the season 2 episode 'One Breath'.
Mulder realizes that the clones of the young boy he saw working with his sister's clones in the season's premiere Herrenvolk, are younger clones from the Kurt Crawford series.
Just before Mulder goes into the lab with the Kurt Crawford clones, Byers sees the police getting out of their car at the front of the lab complex. Mulder spends several minutes in the lab with the clones; the scene then cuts to Byers at the front again and the police are just a few feet from their vehicle, although quite a few minutes have passed.
- Sheila Larken as Margaret Scully
- David Lovgren as Kurt Crawford
- Gillian Barber as Penny Northern
- Tom Braidwood as Melvin Frohike
- Dean Haglund as Richard Langly
- Bruce Harwood as John Fitzgerald Byers
- Vanessa Morley as Young Samantha Mulder (uncredited)