The official trailer for the Arrowverse Elseworlds crossover even has arrived. For several years now, The CW’s shared DC TV universe has held annual crossovers inspired by famous comic book stories like Invasion! and Crisis on Earth-X. The trend continues in December, as Arrow, The Flash, and Supergirl are once again coming together; this time, in a story where reality itself has been rewritten. DC’s Legends of Tomorrow is sitting this year’s crossover out, but is going to be hosting its own “event” around the same time.

Elseworlds kicks off when Arkham Asylum Dr. John Deegan (Jeremy Davies) gets ahold of an item that allows him to rewrite the fabric of reality, resulting in a world where Oliver Queen (Stephen Amell) is now Barry Allen/The Flash and the real Barry (Gran Gustin) is now Oliver/Green Arrow. Likewise, Kara Danvers/Supergirl (Melissa Benoist) is shocked to find that her sister Alex (Chyler Leigh) no longer knows who she is and even jails her in a metahuman holding cell. As the newly-released Elseworlds trailer reveals, however, this is really all the doing of Mar Novu aka. The Monitor (LaMonica Garrett).

The Elseworlds trailer confirms that The Monitor is the one responsible for giving Dr. Deegan the (presumably, magical) item that allows him to rewrite the world as it exists, for reasons that have yet to be revealed. In addition to highlighting the Elseworlds versions of The Flash and Green Arrow, the promo offers another glimpse at Tyler Hoechlin’s Superman in his black suit (another after-effect of Deegan meddling with reality) and John Wesley Shipp (seemingly playing Jay Garrick again) in his 1990s The Flash TV show costume. Take a look in the space below.

Arguably, though, the most exciting thing about Elseworlds is that it serves as an introduction to the Arrowverse version of Kate Kane/Batwoman, as played by Ruby Rose (Orange is the New Black). The character is going to make her debut during the Arrow hour of the three-night event and can be glimpsed briefly in the official trailer (following the release of a Batwoman-centric Elseworlds promo last week). Elseworlds further promises to address fans’ questions about Batman in the Arrowverse and set the stage for Batwoman to lead a series of her own on The CW next year.

Between the fun of seeing superheroes swap identities, comic book easter eggs like Superman wearing his infamous black suit, and the world-building with Batwoman, Elseworlds has the potential to be both an entertaining crossover and an essential addition to the larger Arrowverse’s mythology. The event seems somewhat darker overall that certain crossovers past, but that’s only fitting in light of what’s happening in the Arrowverse right now. Indeed, between the growing anti-alien violence on Supergirl, Cicada’s metahuman murder spree on The Flash, and Oliver’s experiences in prison on Arrow, a story involving hammy bad guys like Dr. Deegan and The Monitor changing reality feels almost light-hearted by comparison.

MORE: Every Superhero in the Arrowverse

Elseworlds begins with The Flash on Sunday, December 9, then Arrow on Monday, December 10, and ends with Supergirl on Tuesday, December 11. All episodes air at 8pm.

Source: The CW