When it comes to X-Files fans, there’s something of a divide between those who prefers the loose, somewhat convoluted through-storyline of the series, and who prefer the standalone episodes (which often explore more outlandish plot lines). Many of the greatest episodes — from the banned “Home,” to the freakshow-centric “Humbug,” to the cyberpunk paranoia of “Kill Switch,” to the dreamlike “Beyond the Sea” — are standalones, not essential to the central “plot.”

But if you’re struggling to get familiar with — or catch up — on the backstory prior to checking out the reboot miniseries that premieres this Sunday on FOX, here’s a complete, chronological list of the episodes that will explain the questions Mulder and Scully are still trying to answer.

Parentheses denote less plot-essential episodes. Episodes listed together are two-part sagas.

Major, life-ruining spoilers are not included in these descriptions, only kernels to indicate the trajectory and narrative importance of each episode.

Season 1

The first season builds the mythology for the entire series, so in some sense it’s really worth cruising through the first five to get a sense of the universe — to understand Mulder’s obsession with extraterrestrial life and government conspiracies due to the abduction of his sister Samantha, and Scully’s skepticism, as an agent coming out of the medical profession.

Pilot — Everything is laid out. We get our first glimpse of the paranormal, Scully reveals the strange tale of his sister, Mulder sees a UFO and Scully doesn’t. We meet the Cigarette Smoking Man (William E. Davis) and FBI Assistant Director Walter Skinner (Mitch Pileggi).

Deep Throat — The introduction of “Deep Throat” (Jerry Hardin), the government informer who hands Mulder the big stuff in Season 1.

E.B.E. — Mulder and Scully get really close to tracking down an alien in possession of the government, explore the connection between ETs and Gulf War syndrome. We meet the Lone Gunmen — Richard “Ringo” Langly (Dean Haglund), Melvin Frohike (Tom Braidwood), and John Fitzgerald Byers (Bruce Harwood) — for the first time.

The Erlenmeyer Flask — Scully uncovers something very big sneaking around Fort Marlene, a secret government facility. Experimentation on humans with virus strains from ETs? That’s not all. A cathartic run-in with Deep Throat. The X-Files project is shut down.

Season 2

Little Green Men — A depressed Mulder makes an unexpected, highly classified discovery on a tape reel in Puerto Rico.

(The Host) — Beware the ghastly flukeworm of the sewers! Mr. “X” (Steven Williams) becomes Mulder’s new informant.

(Sleepless) — The cover-up of a Vietnam-era government experiment that results in sleeplessness and uncanny powers.

Duane Barry and Ascension — A sinister, erratic former FBI agent goes AWOL. Scully is kidnapped, finds herself face-to-face with alien life once again and disappears. Alex Krycek (Nicholas Lea) becomes a major player and Mulder’s surrogate partner, and Cigarette Smoking Man is at the fore.

One Breath — The dreamy, troubled return of Scully, featuring face-offs with X, Skinner and the Cigarette Smoking Man.

Colony and End Game — Samantha appears for the first time. Mulder and Scully learn of and track an alien bounty hunter masquerading as human(s), before Scully — once again — is put in harm’s way.

Anasazi — Definitely a classic, and one of the great cliffhangers of the series. A “digital tape” comes courtesy of a strange hacker with ties to the Lone Gunmen, but it’s coded in Navajo. It leads Mulder to find evidence of Nazi-informed bioengineering in a boxcar buried under rock and ash in New Mexico.

Season 3

The Blessing Way and Operation Paper Clip — continuation of “Anasazi.” Mulder is revived from a netherworld. Agents come after Scully, who has gone rogue, in an attempt to clean up the mess set off by the leak of the tape. Skinner stands up to the Cigarette Smoking Man. “Well Manicured Man” (John Neville) appears, and Mulder and Scully visit a breakdown mine in West Virginia harboring one of America’s darkest secrets.

Nisei and 731 — A video of an alien autopsy comes into Mulder’s possession, and another international conspiracy centering around Japan comes to light. Scully meets other victims of abduction, by the same party who took her. Mulder jumps onto a train, and learns the horrible truth.

Piper Maruand Apocrypha — Explores, among other things, the investigation of the murder of Scully’s sister, and the strange case of Alex Krycek — disturbed former Cigarette Smoking Man crony. Plenty of action with the Smoking Man, the Syndicate and, ultimately, the apprehension of a cold-blooded killer. Skinner gets himself in serious danger.

Talitha Cumi — Season finale: An important, revelatory look into Mulder’s twisted family life. The bounty hunter is on the loose again. The Smoking Man is ill.

Season 4

Herrenvolk — The Bounty Hunter chases Mulder. “X” is in trouble, and Samantha returns. A new informant for Mulder, Marita Covarrubias (Laurie Holden), arrives. The Smoking Man’s character and his motivations become even more complicated.

Musings of a Cigarette Smoking Man— Required viewing. Extremely goofy, but features crucial backstory on The Cigarette Smoking Man. Flashbacks and Frohike. Reads almost like fan-fiction about CSM.

Tunguska and Terma— Mulder, Scully and Krycek work together in an attempt to secure part of a meteor with alien bacteria on it. Heavy on the Syndicate. Mulder AWOL in a Russian gulag.

Memento Mori — Health complications from Scully’s Season 2 abduction come to a head.

Zero Sum — An episode that focuses on Skinner, who makes a deal with the devil (the CSM, as you might imagine) which forces him to deceive Mulder. Scully does not appear in the episode.

Gethsemane — Season finale: Mulder, as usual, hunting an alien body, with deadly consequences. Creator Chris Carter has described the episode as being his way of pondering “the existence of God.” Ends on the most startling cliffhanger of the series.

Season 5

Redux and Redux II — An essential two-parter, which finds Scully’s fate in the hands of The Cigarette Smoking Man, and Mulder being forced towards making a deal. Samantha returns to drop even more shocking information on Mulder. A real mindbender.

Christmas Carol and Emily— A shocking examination of Scully’s family tree, and more details about her abduction.

Patient X and The Red and the Black — A new alien race, the introduction of recurring characters Jeffrey (Chris Owens) and Cassandra Spender (Veronica Cartwright), the Syndicate does brutal testing, Mulder puts Scully under hypnosis to uncover more detailed about a new type of conspiracy he is piecing together.

(Travellers) — Weird X-Files origin story episode featuring a young Mulder.

The End — A false ending for the TV show, as Carter and Co. hoped to move the X-Files universe into film. The episode revolves around a chess master with potentially aberrant gene, but ends up in a cathartic showdown with The Smoking Man and a plot to terminate the X-Files for good. Every living, significant character features in the episode.

Movie 1: Fight the Future

The movie takes place between Seasons 5 and 6, during a time when Mulder and Scully are not working as agents, but fall into investigating … you guessed it, a government conspiracy with the Smoking Man at the center of everything. Scully is hidden away in a secret base in Antarctica. Not very good, and certainly not much different than a too-long regular episode. Advances the show only in superficial ways.

Season 6

The Beginning — Jeffrey Spender (Chris Owens) and Diana Fowley (Mimi Rogers) have taken over the X-Files at the FBI. Mulder and Scully work on the side, dealing with a new, sordid alien threat. Filming of the show relocates to Los Angeles — some view the most accessible, less daring season as being evidence of the show jumping the shark.

S.R. 819 — Skinner is on his deathbed from a ugly, vein-popping alien disease, and Mulder and Scully scramble to determine a cure. The always unpredictable Krycek shows up.

Two Fathers and One Son— An alien uprising puts the Syndicate on the defensive. The episode features a new exploration of the complex relationship between the Smoking Man, Jeffrey Spencer, and Mulder.

Biogenesis — A rock with Navajo writing (remember, Season 2 finale and those alien-vibing Native Americans!) in Africa drives Mulder literally insane. This is a pretty crucial, expansive and batshit episode which questions the very origins of life on Earth and the roots of the human race, because at this point, what else was left to explore? Death, deception, and a huge advancement for the series’ mythology.

Season 7

The Sixth Extinction and The Sixth Extinction II: Amor Fati — A continuation of the Season 6 finale. As the title suggests, Scully’s rooting around in Africa gets at the involvement of extraterrestrials in the extinction of pre-human species. Mulder is still institutionalized and addled, attended to by Skinner. The second part of the episode — co-written by Duchovny and Chris Carter — is set in a dream-world, and was inspired by the novel and film of The Last Temptation of Christ, so it is, as you can imagine, some heavy and odd shit.

Sein und Zeit and Closure — Yes, philosophy nerds, the first part is named for a Heidegger text. This two-parter gets, once and for all, at the explanation for Samantha Mulder’s disappearance, and explores Mulder’s family in depth. Essential viewing for the mythology.

Requiem — Season Finale: Going in depth here at all would make for major spoilers, but suffice to say, we learn some very important things about Scully, as her health grows increasingly uncertain. The Smoking Man appears, attempting to make a resurgence to power. Mulder’s future has never been more uncertain.

Season 8

Full disclosure: Mulder is gone for this whole season; Duchovny had signed off as a full-time member of the cast for the first half of the season, but appears in flashbacks and marginally. Scully partners with John Doggett (Robert Patrick) and investigates the details of his abduction. There are a lot of very unsubtle Jesus allusions in regards to Mulder. No one was really sure how long the show was going to last, and lots of the tension left the show after the revelations of Season 7 in the episodes above. Too many reveals about this season would give a lot away, but here are the episodes which further the central storyline.

“+” denotes more important/worthwhile.

Within and Without +

Per Manum

This is Not Happening

Deadalive+ — Mulder is found, in a comatose, uncertain state.

Three Words+ — Mulder returns to unsanctioned work, with Doggett still holding his place as Scully’s partner, and signals the beginning of the end of his involvement with the FBI for the rest of the chronology.

Vienen+— Mulder works with Doggett in a return to the recurring alien “black oil” plotline, and passes on his role to Doggett at the bureau for good. Mulder plays a most ancillary role for the rest of the season, working on the sidelines of the investigations. Probably the best episode of Season 8.

Essence and Existence+ — TWO VERY IMPORTANT THINGS HAPPEN HERE. Essential to watch prior to viewing Episode 1 of the new series.

Season 9

The season came both post-9/11 and post-Duchovny, and had at least two too many main characters. Mulder is in hiding, Scully is off The X-Files and Monica Reyes (Annabeth Gish) and Doggett are the new agents in charge This season is definitely a slog, one relatively few have made in full, focusing around a government plot to make “SuperSoldiers” or genetically enhanced soldiers. More marginally — but more interestingly, in terms of the wider mythology — a UFO cult is out to get Scully.

Nothing Important Happened Today+

Nothing Important Happened Today II+

Trust No. 1

Provenance

Providence

Jump The Shark — The conclusion of the Lone Gunmen storyline. This also provided closure (and a nice ironic title) as the The Lone Gunmen spinoff show had been cancelled mid-season earlier that year.

William+ — Relates to the Season 8 two-part finale; also instructive before watching Episode 1 of the new series.

Release

The Truth+

The Truth II+ — Mulder returns. LOTS OF THINGS CONCLUDED, UNEXPECTED PEOPLE RETURN!

Movie #2: I Want to Believe

The Xzibit-featuring The X-Files: I Want to Believe — which takes place after the end of the series — is generally unrelated to the “mythology” of the film. From an overarching perspective, it was designed as Carter and Duchovny clarified, as a “monster of the week”-type standalone episode in movie form. It sets up the conceit — maintained in the premiere of the new series — that Scully is working at a Catholic hospital while Mulder remains a disgruntled free agent, searching for “the truth” all on his eccentric own.

Now, get ready for:

For another Inverse list of highly enjoyable X-Files fare, check here.