The series centers on Federal Bureau of Investigation (FBI) special agents Fox Mulder (David Duchovny) and Dana Scully (Anderson) who work on cases linked to the paranormal, called "X-Files".

In this episode, a series of coincidences lead Scully to meet Dr. Daniel Waterston (Nicolas Surovy), a married man with whom she had an affair while at medical school.

As she leaves, her colleague Fox Mulder (David Duchovny) lies in his bed, half of his body covered by bedsheets.

The narrative flashes back to a few days earlier: Scully arrives at a hospital and, after a series of coincidences, meets her former professor, Daniel Waterston (Nicolas Surovy), with whom she had an affair while attending medical school.

Mulder begins to speak more existentially about what transpired, implying that fate has brought them together but, when he turns to look at Scully, he sees that she has fallen asleep.

Sometime during the sixth season of The X-Files, Anderson approached series creator Chris Carter and asked to write an episode that explored her own interest in "Buddhism and the power of spiritual healing"; ultimately, she wanted to write a script in which Scully pursued a "deeply personal X-File, one in which [she] is taken down a spiritual path when logic fails her".

[5] She wrote the basic outline of what became "all things" in one sitting, which Carter approved due to the "personal and quiet" nature of the story.

[5] Despite her satisfaction with the final version, Anderson regrets a handful of the "necessary" script changes, most notably, the addition that Scully and Waterston's affair was intimate.

[11] The idea of heart chakra crop circles was included because Anderson wanted "whatever Mulder was involved in that took him away from me, away from Washington, to somehow tie into what it was that I was going through—the journey that I was going through".

Around the same time that she approached Carter about writing an episode, Anderson was being solicited by television networks, who were interested in having her direct shows.

"[8] On set, Anderson's directing style was described as "right on the money" by Marc Shapiro in his book all things: The Official Guide to The X-Files, Volume 6.

[8] He later wrote that "Anderson wielded a deft hand in her directorial debut, prodding the actors to her will, making decisions on the fly, and handling the complex special effects sequences".

[8] Anderson was also involved in post-production editing, during which she was forced to cut the final conversation scene between Scully and Daniel Waterston down by about 10 minutes.

[16] In order to create the sequence of Scully visualizing Waterston's heart condition, Nicolas Surovy had to lie naked on a platform surrounded by a blue screen.

A sphere on his chest was matched via motion control as a marker for a prosthetic beating heart that was crafted and filmed separately.

[22] She reasons that the events of the episode open Scully's mind to new ways of knowing, specifically citing "auras, chakras, visions ... and the importance of coincidence".

[27] Despite dabbling in mysticism, a field generally stereotyped as feminine by the patriarchy,[28] Scully engages in "protracted inquiry", examining all sides of the issue, in order to return Waterston to health.

[29] In her academic monograph on the series, Theresa L. Geller considers "all things" at length while discussing the show's sexual politics.

[30] Geller analyzes the episode in the context of Anderson's long-standing engagement with female fans, arguing that it "offers a narrative that acknowledges shippers identification with Scully not as an object of seduction, but as a figure directly impacted by women and changed by what she learns when she listens to them".

[30] Geller sees this intervention as directly tied to the episode's narrative peculiarity: "Although neither FBI-related nor paranormal, 'all things' suggests—and models—ways we can learn from women's knowledge, even when it is intuitive, 'irrational', and embodied.

[37] He did not like Azar and disapproved of Scully's philosophical "reverie", calling it "facile, and hard to reconcile with the determined rationalism she's displayed over the years in the face of events no less strange than those that occur here".

[37] In their book Wanting to Believe: A Critical Guide to The X-Files, Millennium & The Lone Gunmen, Robert Shearman rated the episode one star out of five, calling the premise and characters dull.

Furthermore, Shearman was critical of Anderson's directing style, calling it "pretentious", noting that the plot's significance was drowned out by unnecessary artistic flourishes and needless pizzazz.

[39] She called Anderson's directing "heavy-handed" and bemoaned the storyline because it "plays havoc with Scully's motivations and character as established in the past seven years".

Kinney Littlefield of the Orange County Register wrote that the "wistful, meditative episode" was "not bad for Anderson's first directing effort".