Elseworlds: What You Need to Know Before the Arrowverse Crossover

Elseworlds poster

"Elseworlds" is nearly upon us. Kicking off tonight, the fifth annual Arrowverse crossover unfolds across three participating CW series: SupergirlArrow and The Flash.

In the three-night event, Barry Allen (Grant Gustin) and Oliver Queen (Stephen Amell) awake to discover they've switched bodies, and enlist Team Flash and Supergirl (Melissa Benoist) to find out what could have disrupted the timeline. Their search brings them to Gotham City, where Arkham Asylum doctor John Deegan (Jeremy Davies) is rewriting reality with the help of the mysterious Monitor (LaMonica Garrett). "Elseworlds" brings back Tyler Hoechlin as Superman, and introduces Ruby Rose as Batwoman, Elizabeth Tulloch as Lois Lane, and John Wesley Shipp as The Flash of Earth-90 (that is, The Flash from the 1990s TV show).

That would be enough to unpack on its own, but the crossover also takes place midway through the seasons of The Flash, Arrow and Supergirl. Just in case you haven't been following all three series, we'll bring you up to speed.

Supergirl Season 4 Kara header

So far this year, the Girl of Steel faces a nemesis she can't just punch away: anti-alien sentiment. Under the guidance of Ben Lockwood's Agent Liberty, an international hate movement that calls itself the Children of Liberty is rising on Supergirl's world. While such feelings have long existed on Supergirl, the movement is at an all-time high this season, after President Olivia Marsdin was outed as a Durlan during an attack coordinated by terrorists Mercy and Otis Graves.

RELATED: Elseworlds: Supergirl's Benoist Teases 'Heartwarming' Smallville Scenes

As a result, Marsdin was forced to step aside. Vice President Baker was subsequently installed as the new president of the United States. Though he was pleasant enough to Supergirl at first, this facade soon began to unravel. After the Graves siblings attacked a local fair using brainwashed aliens, which pulled the D.E.O. into a very public spectacle, he installed Colonel Lauren Haley to oversee operations. This seriously kneecapped D.E.O. Director Alex Danvers, who is no longer able to pursue threats without Haley's approval. Worse, both Haley and Alex are subject to Baker's whims, and he seems more concerned with his ratings and his donors than he does with national security.

This came to a head in the midseason finale "Bunker Hill." When Supergirl publicly arrested Agent Liberty, Baker's donors were upset, so he personally paid the D.E.O. a visit to berate Alex and Haley. Picking up on something Lockwood said -- specifically, that he was demonized for wearing a mask while no one knew who Supergirl really was -- Baker demanded full transparency from the Girl of Steel. She refused, due to the fact that those she loved could be hurt if her true identity fell into the wrong hands, and was forced to end her association with the D.E.O. despite Alex's protests.

RELATED: Elseworlds Will Pit Supergirl Against Superman in 'Dynamo' Fight Scene

As it stands, then, Supergirl has been cut off from the support system she's had since Season 1. It seems Alex, her sister and confidant, will remain at the D.E.O. with Brainiac-5 to mitigate the damage. Meanwhile, J'onn Jonzz, aka Martian Manhunter, continues to struggle with his desire to help people and his promise to his father that he would pursue non-violent ways.

Next Page: Arrow's Prison Blues

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