S7E10 · Sein und Zeit

Fox Mulder (David Duchovny) asks to be a part of the investigation looking for a little girl, Amber Lynn LaPierre, who disappeared from her home in Sacramento, California. Mulder's superior, Walter Skinner (Mitch Pileggi), initially denies his request, noting that the investigation is not an X-file, but simply a missing persons case. Mulder, however, convinces Skinner to allow him to investigate. The parents of Amber, Billie and Bud, tell Mulder that they found a note in the girl's bedroom, but the teaser for the episode revealed that the note was written by Billie herself.

The note contains a mention of Santa Claus, which everyone finds out of place. Although the family is held for questioning, Mulder does not believe they did it. Looking through previous cases, Mulder finds a similar note, with a reference to Santa Claus, from a missing person case in Idaho from 1987. In the case, the mother was convicted and sentenced to twelve years. The file notes that she had a vision of her son dead before he disappeared, as did Bud on the night his daughter disappeared.

Meanwhile, Mulder's mother Teena is found dead in her home. It is found she overdosed on sleeping pills after she burned all her pictures of Samantha and placed tape around her baseboards and turned the gas in the oven on. Mulder believes she was murdered and has Dana Scully (Gillian Anderson) do an autopsy. Later, Mulder visits the mother who was convicted twelve years prior. She tells him that Samantha is a walk-in, a kind spirit who takes children so that they may be shielded from potential harm in their life.

The mother tells Mulder that the children are safe, but she has no idea where they are. After hearing this, Mulder believes his mother probably also wrote a note after his sister's disappearance. He begins to think that the alien abduction never happened, and that his mother figured this out, which is why she was murdered. However, after performing the autopsy, Scully tells Mulder that it was definitely suicide, because she was ill with Paget's carcinoma.

During the happenings of the episode, a man playing Santa at a Christmas-themed ranch is shown videotaping the children at his ranch. Billie later tells Mulder that she saw a vision of her daughter in her room and that she said the number 74. Mulder decides he cannot finish the case and wants to take time off because he's too close to make any sound judgment. On their way to the airport, Scully comes across the Santa park (situated off of California State Route 74) and decides to stop because of the reference to Santa Claus in the notes. Here they find the videotape setup and tapes dating back to the 1960s, including one of Amber Lynn LaPierre. The man who runs the park is promptly arrested, and Mulder finds graves of children all over his ranch.