# Crisis on Earth-X
**Crisis on Earth-X** is the fourth annual crossover event of the [Arrowverse](https://www.edgepedia.org/arrowverse), the shared television universe built around [The CW](https://www.edgepedia.org/the-cw)'s DC Comics shows, aired in November 2017 as a four-part story across *Supergirl*, *Arrow*, *The Flash*, and *DC's Legends of Tomorrow*[1](https://arrow.fandom.com/wiki/Crisis_on_Earth-X). The title comes from Earth-X, an alternate Earth in [DC Comics](https://www.edgepedia.org/dc-comics)' Multiverse where the Nazis won World War II and took over the planet; the name itself nods to the many "crisis" events DC has published since *Crisis on Infinite Earths* introduced the concept of the Multiverse[2](https://www.dc.com/blog/2017/12/21/ten-moments-that-mattered-dct-vs-crisis-on-earth-x) • [3](https://www.dc.com/blog/2017/09/22/breaking-news-a-crisis-of-a-crossover). Unlike earlier crossovers that split two loosely connected stories, it tells a single continuous story: heroes from several Earths unite against an invading force of Nazi doppelgangers led by evil versions of Supergirl and Oliver Queen[4](https://www.comicsbeat.com/all-the-arrowverse-crossovers-ranked/).
| Key fact | Detail |
|---|---|
| Event | Fourth annual Arrowverse crossover, spanning *Supergirl*, *Arrow*, *The Flash*, and *DC's Legends of Tomorrow*[1](https://arrow.fandom.com/wiki/Crisis_on_Earth-X) |
| Broadcast | Two nights, four parts: Monday, November 27 and Tuesday, November 28, 2017 on The CW[3](https://www.dc.com/blog/2017/09/22/breaking-news-a-crisis-of-a-crossover) |
| Episode order | Supergirl, then Arrow, then The Flash, then Legends of Tomorrow[5](https://as.com/meristation/noticias/en-que-orden-ver-las-peliculas-y-series-del-universo-dc-orden-cronologico-y-estreno-n/) |
| Premise | Invaders from Earth-X, a world where the Nazis won World War II, attack during Barry Allen and Iris West's wedding[2](https://www.dc.com/blog/2017/12/21/ten-moments-that-mattered-dct-vs-crisis-on-earth-x) • [6](https://www.rottentomatoes.com/tv/the_flash/s04/e08) |
| Villains | Overgirl (an evil Supergirl), the Earth-X Oliver Queen as Black Arrow, plus Prometheus-X, Dark Flash, and Metallo[2](https://www.dc.com/blog/2017/12/21/ten-moments-that-mattered-dct-vs-crisis-on-earth-x) |
| Lasting changes | Martin Stein of Firestorm killed; Barry–Iris and Oliver–Felicity married in a joint ceremony; The Ray debuts in live action[2](https://www.dc.com/blog/2017/12/21/ten-moments-that-mattered-dct-vs-crisis-on-earth-x) • [3](https://www.dc.com/blog/2017/09/22/breaking-news-a-crisis-of-a-crossover) |
| Ratings | Part 3 drew 2.74 million viewers (0.9 demo); the finale drew 2.76 million (0.9), a high for Legends since "Invasion!"[7](https://www.tvline.com/ratings/arrowverse-crossover-ratings-crisis-earth-x-flash-legends-890774/) |
## Premise
The story begins with a wedding. Barry Allen ([The Flash](https://www.edgepedia.org/the-flash)) and [Iris West](https://www.edgepedia.org/iris-west) gather friends and family from across the [Multiverse](https://www.edgepedia.org/multiverse), and the ceremony is attacked by villains from Earth-X[6](https://www.rottentomatoes.com/tv/the_flash/s04/e08). Earth-X is an alternate Earth where the Nazis won World War II and took over the planet; it is home to twisted versions of familiar heroes, led by an evil Supergirl called Overgirl, who is married to the Earth-X version of Oliver Queen, known as Black Arrow[2](https://www.dc.com/blog/2017/12/21/ten-moments-that-mattered-dct-vs-crisis-on-earth-x). They command a crew of fascist villains including Prometheus-X, Dark Flash, and Metallo[2](https://www.dc.com/blog/2017/12/21/ten-moments-that-mattered-dct-vs-crisis-on-earth-x).
The invaders have recently discovered how to travel through the Multiverse and set out to conquer other Earths[4](https://www.comicsbeat.com/all-the-arrowverse-crossovers-ranked/). Earth-X is not without its own resistance: a band of rebels called the Freedom Fighters, including the hero The Ray and an alternate version of Leonard Snart, works to destroy the Nazi regime on their own world[2](https://www.dc.com/blog/2017/12/21/ten-moments-that-mattered-dct-vs-crisis-on-earth-x).
**Structure.** All four episodes carry the "Crisis on Earth-X" title rather than their own episode title cards, but not every character from every series appears in every episode[4](https://www.comicsbeat.com/all-the-arrowverse-crossovers-ranked/) • [16](https://www.thedirect.com/article/arrowverse-crossover-episodes-watch-order). The Comics Beat review describes the result as essentially a four-hour movie featuring every hero on Earth-1, plus several from Earth-38, united against the invaders[4](https://www.comicsbeat.com/all-the-arrowverse-crossovers-ranked/). [Stephen Amell](https://www.edgepedia.org/stephen-amell), who plays Oliver Queen, promoted the event in the same terms before it aired, teasing four episodes that would feel like a single film[8](https://comicbook.com/dc/news/arrowverse-crossover-2017-the-cw-stephen-amell-arrow/).
## Production and announcement
The CW and Warner Bros. Television announced the title in September 2017, along with the broadcast plan: unlike past crossovers spread over separate weeks, this one would air over two consecutive nights, November 27 and 28, with *Arrow* temporarily moved from its Thursday slot to follow *Supergirl* on Monday[3](https://www.dc.com/blog/2017/09/22/breaking-news-a-crisis-of-a-crossover).
Executive producers Marc Guggenheim and Andrew Kreisberg said the crossover was conceived to evoke the annual [Justice League](https://www.edgepedia.org/justice-league)/Justice Society comic crossovers of earlier decades; artist Phil Jimenez, known for his work on *Wonder Woman* and *Superwoman*, drew a promotional comic cover whose design invokes *Justice League* #207, the 20th annual JLA/JSA crossover[3](https://www.dc.com/blog/2017/09/22/breaking-news-a-crisis-of-a-crossover). The crossover also served to launch characters and promotion beyond the four shows: fans got their first look at Earth-X in a sneak peek of the animated *[Freedom Fighters: The Ray](https://www.edgepedia.org/freedom-fighters-the-ray)* digital series that summer, and The Ray made his live-action debut in the event[3](https://www.dc.com/blog/2017/09/22/breaking-news-a-crisis-of-a-crossover) • [9](https://novastreamnetwork.com/dc-domination/review-criss-earth-x/).
Later, Guggenheim and [Greg Berlanti](https://www.edgepedia.org/greg-berlanti) described "Crisis on Earth-X" as very trying to produce because of its size and scope, while still counting it among their greatest accomplishments with the Arrowverse[10](https://sciencefiction.com/2019/12/04/building-a-crisis-arrowverse-producers-speak-on-the-history-of-their-crossovers/).
## Story consequences
The event changed the status quo of three of the four series[2](https://www.dc.com/blog/2017/12/21/ten-moments-that-mattered-dct-vs-crisis-on-earth-x). Barry Allen and Iris West married, as the crossover had been built around their wedding, and Oliver Queen and [Felicity Smoak](https://www.edgepedia.org/felicity-smoak) joined them in the same joint ceremony, presided over by John Diggle[2](https://www.dc.com/blog/2017/12/21/ten-moments-that-mattered-dct-vs-crisis-on-earth-x). Felicity had hesitated right up to the last second, making the second marriage the less expected of the two[2](https://www.dc.com/blog/2017/12/21/ten-moments-that-mattered-dct-vs-crisis-on-earth-x).
Professor Martin Stein, one half of the [Firestorm](https://www.edgepedia.org/firestorm) matrix on *Legends of Tomorrow*, was killed during the event; he died a hero after long wanting to retire from superhero life, and his partner Jax lost access to Firestorm's powers as a result[2](https://www.dc.com/blog/2017/12/21/ten-moments-that-mattered-dct-vs-crisis-on-earth-x). In exchange, the Legends gained a temporary member: Earth-X's Citizen Cold, Leo Snart, stayed aboard the Waverider[2](https://www.dc.com/blog/2017/12/21/ten-moments-that-mattered-dct-vs-crisis-on-earth-x). Afterward, The Ray starred in his own animated series on CW Seed, and a mystery girl, first appearing in the [Supergirl](https://www.edgepedia.org/supergirl) installment of the crossover, was later revealed to be Nora West-Allen, Barry and Iris's daughter from the future, and became a series regular in *The Flash* season five[4](https://www.comicsbeat.com/all-the-arrowverse-crossovers-ranked/) • [17](https://www.tvguide.com/news/the-flash-season-4-jessica-parker-kennedy-mystery-girl-clues/).
## Reception
The crossover earned largely positive reviews and strong audience response. On its first night it briefly trended at number one on Twitter, ahead of every other topic worldwide; the AIPT review contrasted this with the poor reception of the *Justice League* film released the same month, noting that the Arrowverse roster lacked A-list heroes and still outperformed the blockbuster in reception[11](https://aiptcomics.com/2017/11/29/crisis-on-earth-x-succeeds-where-justice-league-failed/). ComicBook.com likewise reported that reviews skewed extremely positive from fans and critics, and framed the event as a ratings boon for The CW[12](https://comicbook.com/dc/news/crisis-on-earth-x-is-what-dc-needed-after-justice-league/).
The ratings bore that out. Part 3, airing Tuesday, drew 2.74 million viewers and a 0.9 rating in the adults 18–49 demo, the best numbers for *The Flash* since its season opener; the finale drew 2.76 million and a 0.9, nearly doubling *Legends of Tomorrow*'s previous week and marking that show's best numbers since the prior year's "[Invasion!](https://www.edgepedia.org/invasion-arrowverse)"[7](https://www.tvline.com/ratings/arrowverse-crossover-ratings-crisis-earth-x-flash-legends-890774/). On the review aggregator Rotten Tomatoes, *The Flash* season 4 episode 8 holds an 89% Tomatometer score and *Supergirl* season 3 episode 8 a 93% score[6](https://www.rottentomatoes.com/tv/the_flash/s04/e08) • [13](https://www.rottentomatoes.com/tv/supergirl/s03/e08).
Among retrospective rankings, Comics Beat placed "Crisis on Earth-X" first of all Arrowverse crossovers as of 2018, praising its stakes and structure[4](https://www.comicsbeat.com/all-the-arrowverse-crossovers-ranked/). It is frequently held up, in fan discussion and reviews, as the model the later "Crisis on Infinite Earths" crossover was measured against[4](https://www.comicsbeat.com/all-the-arrowverse-crossovers-ranked/).
## Legacy
The event cemented the two-night, four-show format and set a template for large-scale television crossovers on a network budget. Its use of Earth-X drew on comics history: Earth-X first appeared in DC's *Justice League of America* #107 (1973), a world where [Nazi Germany](https://www.edgepedia.org/nazi-germany) won World War II[14](https://www.tomsguide.com/entertainment/hbo-max/peacemaker-season-2-may-be-heading-for-a-shocking-reveal-if-this-fan-theory-is-true-and-i-think-it-is). The Arrowverse's other annual crossovers followed, culminating in "Crisis on Infinite Earths" (2019–2020), which reshaped the shared universe; retrospective comparisons often favor "Crisis on Earth-X" for its self-contained story, even though not every major character appears in every episode[4](https://www.comicsbeat.com/all-the-arrowverse-crossovers-ranked/) • [16](https://www.thedirect.com/article/arrowverse-crossover-episodes-watch-order). The four episodes were later collected for purchase as a single 92-minute feature[15](https://www.justwatch.com/us/tv-show/crisis-on-earth-x).
## References
1. [Crisis on Earth-X, Arrowverse Wiki](https://arrow.fandom.com/wiki/Crisis_on_Earth-X)
2. [Ten Moments that Mattered: #DCTV's Crisis on Earth-X, DC.com (December 21, 2017)](https://www.dc.com/blog/2017/12/21/ten-moments-that-mattered-dct-vs-crisis-on-earth-x)
3. [Breaking News: A Crisis of a Crossover, DC.com (September 22, 2017)](https://www.dc.com/blog/2017/09/22/breaking-news-a-crisis-of-a-crossover)
4. [All the Arrowverse Crossovers, Ranked, Comics Beat (December 14, 2018)](https://www.comicsbeat.com/all-the-arrowverse-crossovers-ranked/)
5. [En qué orden ver las películas y series del Universo DC, AS MeriStation (2023)](https://as.com/meristation/noticias/en-que-orden-ver-las-peliculas-y-series-del-universo-dc-orden-cronologico-y-estreno-n/)
6. [The Flash: Season 4, Episode 8, Rotten Tomatoes](https://www.rottentomatoes.com/tv/the_flash/s04/e08)
7. [Ratings For Arrowverse Crossover Parts 3 And 4, TVLine (2017)](https://www.tvline.com/ratings/arrowverse-crossover-ratings-crisis-earth-x-flash-legends-890774/)
8. ['Arrow's Stephen Amell Teases "Crisis On Earth-X" Crossover As A 4-Hour Movie, ComicBook.com](https://comicbook.com/dc/news/arrowverse-crossover-2017-the-cw-stephen-amell-arrow/)
9. [Review: Crisis on Earth-X, Novastream (2017)](https://novastreamnetwork.com/dc-domination/review-criss-earth-x/)
10. [Building A Crisis: Arrowverse Producers Speak On The History Of Their Crossovers, ScienceFiction.com (2019)](https://sciencefiction.com/2019/12/04/building-a-crisis-arrowverse-producers-speak-on-the-history-of-their-crossovers/)
11. ['Crisis on Earth-X' succeeds where 'Justice League' failed, AIPT (November 29, 2017)](https://aiptcomics.com/2017/11/29/crisis-on-earth-x-succeeds-where-justice-league-failed/)
12. ["Crisis on Earth-X" Is What DC Needed After 'Justice League', ComicBook.com (2017)](https://comicbook.com/dc/news/crisis-on-earth-x-is-what-dc-needed-after-justice-league/)
13. [Supergirl: Season 3, Episode 8, Rotten Tomatoes](https://www.rottentomatoes.com/tv/supergirl/s03/e08)
14. [Peacemaker season 2 finally reveals the truth about its parallel Earth, Tom's Guide (2024)](https://www.tomsguide.com/entertainment/hbo-max/peacemaker-season-2-may-be-heading-for-a-shocking-reveal-if-this-fan-theory-is-true-and-i-think-it-is)
15. [Crisis on Earth-X, JustWatch](https://www.justwatch.com/us/tv-show/crisis-on-earth-x)
16. [How to Watch All 10 Arrowverse Crossovers In Order](https://www.thedirect.com/article/arrowverse-crossover-episodes-watch-order)
17. [The Flash: Who Is the Mystery Girl? All the Clues Explained - TV Guide](https://www.tvguide.com/news/the-flash-season-4-jessica-parker-kennedy-mystery-girl-clues/)
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*Topic: Encyclopedia › Arts and culture › Screen and stage › Film and television › Series and fictional screen worlds › Scripted television and comedy series › Adapted and franchise screen series › Franchise crossovers and shared-universe events*
*Initially written Sep 17, 2026 · Reviewed: Oct 25, 2026 · Edited: Oct 15, 2026; Oct 25, 2026 · Last review: Oct 25, 2026*
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License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license