"The X-Files" is known for having two types of episodes: "Monster-of-the-Week" (MOTW) episodes, which are self-contained stories, and "Mythology" episodes, which are part of the larger narrative concerning the existence of extraterrestrials and a government conspiracy to hide their presence from the public. To follow the main story arc, you'll want to focus on the mythology episodes. Here is a list of episodes from the original run (seasons 1–9) and the two revival seasons (10 and 11) that primarily focus on the overarching mythology. Note that while this list covers the key episodes, watching only the mythology arc may result in missing out on some of the character development and nuance found in the MOTW episodes. ### Season 1: - 1x01: "Pilot" - 1x02: "Deep Throat" - 1x09: "Fallen Angel" - 1x10: "E.B.E." - 1x17: "The Erlenmeyer Flask" ### Season 2: - 2x01: "Little Green Men" - 2x05: "Duane Barry" - 2x06: "Ascension" - 2x08: "One Breath" - 2x10: "Red Museum" (has ties to the mythology) - 2x16: "Colony" - 2x17: "End Game" - 2x25: "Anasazi" ### Season 3: - 3x01: "The Blessing Way" - 3x02: "Paper Clip" - 3x09: "Nise, Part 1" - 3x10: "731, Part 2" - 3x15: "Piper Maru" - 3x16: "Apocrypha" - 3x24: "Talitha Cumi" ### Season 4: - 4x01: "Herrenvolk" - 4x07: "Musings of a Cigarette Smoking Man" (mostly background information) - 4x08: "Tunguska" - 4x09: "Terma" - 4x14: "Memento Mori" - 4x17: "Tempus Fugit" - 4x18: "Max" - 4x21: "Zero Sum" - 4x23: "Demons" - 4x24: "Gethsemane" ### Season 5: - 5x01: "Redux" - 5x02: "Redux II" - 5x03: "Unusual Suspects" (backstory of The Lone Gunmen) - 5x06: "Christmas Carol" - 5x07: "Emily" - 5x13: "Patient X" - 5x14: "The Red and the Black" - 5x15: "Travelers" (some backstory) - 5x20: "The End" (The X-Files Movie: "Fight the Future" comes between seasons 5 and 6) ### Season 6: - 6x01: "The Beginning" - 6x09: "S.R. 819" - 6x11: "Two Fathers" - 6x12: "One Son" - 6x22: "Biogenesis" ### Season 7: - 7x01: "The Sixth Extinction" - 7x02: "The Sixth Extinction II: Amor Fati" - 7x10: "Sein Und Zeit" - 7x11: "Closure" (wraps up Mulder's personal search) - 7x15: "En Ami" - 7x22: "Requiem" ### Season 8: - 8x01: "Within" - 8x02: "Without" - 8x13: "Per Manum" - 8x14: "This is Not Happening" - 8x15: "DeadAlive" - 8x16: "Three Words" - 8x18: "Vienen" - 8x20: "Essence" - 8x21: "Existence" ### Season 9: - 9x01: "Nothing Important Happened Today" - 9x02: "Nothing Important Happened Today II" - 9x06: "Trust No 1" - 9x09: "Provenance" - 9x10: "Providence" - 9x15: "Jump the Shark" (closure for The Lone Gunmen) - 9x16: "William" - 9x19: "The Truth: Part 1" - 9x20: "The Truth: Part 2" ### Season 10 (Revival): - 10x01: "My Struggle" - 10x02: "Founder's Mutation" - 10x06: "My Struggle II" ### Season 11 (Revival): - 11x01: "My Struggle III" - 11x05: "Ghouli" - 11x06: "Kitten" (some Skinner backstory) - 11x10: "My Struggle IV" Remember, "The X-Files" has many enigmatic subplots and a complex lore, so there may be MOTW episodes containing elements relevant to the main story arc or character development that this list does not include. For a fully immersive experience, watching the complete series will give you the most comprehensive understanding and appreciation for both the mythology and the dynamics between characters like Mulder and Scully.