Kara (Melissa Benoist) arrives on Earth-1 in the first trailer for this fall’s highly anticipated four-way crossover event between “Arrow,” “The Flash,” “Supergirl” and “Legends of Tomorrow.”

In the teaser, Barry (Grant Gustin) introduces Kara to characters from “Arrow” and “Legends of Tomorrow.” As seen in the 30-second clip, the Girl of Steel gets to meet Green Arrow (Stephen Amell), White Canary (Caity Lotz), The Atom (Brandon Routh), Heat Wave (Dominic Purcell) and Firestorm (Victor Garber and Franz Drameh), among many others.

The trailer is aptly titled “Heroes Vs. Aliens,” as the protagonists of all four shows are teaming up in the crossover to defeat the Dominators — a race of technologically advanced aliens who believes that the unpredictable evolutionary tendencies of Earth’s metahumans are a threat to the state of the universe.

In the comics, the Dominators connived with other alien races in an attempt to eliminate the metahumans on Earth. “Arrow” and “Legends of Tomorrow” executive producer Marc Guggenheim told Superhero Insider last month that the Dominators’ mission in the crossover is not that different from their main objective in the comics.

“I will say that their goal is very closely related to what was established in the comics, and it does have to do with metahumans,” Guggenheim said.  “It’s very, very faithful to the comics.”

As for how Kara will find her way to Earth-1, Guggenheim said during a press Q&A last month that the heroes in the Arrowverse will reach out to the Kryptonian soon after they find out that their Earth is about to be invaded by a group of aliens. “Once the heroes [in Earth-1] realize that they’re up against aliens, they decide that they need an alien on their side,” Guggenheim said (via Entertainment Weekly). “Fortunately, Barry knows a really nice one.”

“Last year, ‘Supergirl’ established that Flash was able to make his way to what I call Earth-CBS, and it stands to reason that, with the proper breach technology, the reverse can happen,” the exec producer added.

The four-night crossover event, titled “Invasion!,” starts with the Nov. 28 episode of “Supergirl.”

Melissa Benoist as Supergirl Kara (Melissa Benoist) meets Barry’s (Grant Gustin, not pictured) friends in the first trailer for the upcoming four-way crossover event between “Arrow,” “The Flash,” “Supergirl” and “Legends of Tomorrow.” Photo: The CW