‘The Flash,’ ‘Supergirl’ Crossover Teaser, Set Photos Released: How Does Barry Get To National City? [VIDEO]

Kara Zor-El and Barry Allen have two weeks before The Flash / Supergirl crossover on CBS March 28. Supergirl Season 1 episode 17, “Manhunter,” airs March 21. The Flash Season 2 episode 16, “Trajectory,” will air March 22. Hopefully those two episodes will give us a few hints about what’s in store for “World’s Finest.” CBS released a 10-second teaser today that just shows Barry and Kara meet in costume. The biggest question still remains, how will Barry get to National City?

When Barry, Cisco, and Dr. Wells originally traveled to Earth-2, we got a quick flash (no pun intended) of Supergirl flying through the sky [skip to 3:20 on the video below to view]. It’s confirmed The Flash and Supergirl won’t be teaming up on Earth-1, but how the duo will cross paths remains unclear. Barry expressed interest in opening up the portal to Earth-2 once again to save Jay. What Team Flash doesn't know is that Jay is somehow Zoom, or Zoom is Jay….? And who’s the guy behind the iron mask? The last episode of The Flash, “King Shark,” answered none of our burning questions.

We have a few hints as to what’s going to go on between the characters in National City. Melissa Benoist suggested during an interview that James Olsen may get a little jealous of Barry and Kara’s superhero chemistry. DC Comics has released a poster that confirms there will be a race between Barry and Kara, like the Man of Steel vs. The Flash in the comics.

Leaked set photos reveal The Flash, Supergirl, Silver Banshee, and Livewire, so it’s safe to assume those are the two supervillains Barry and Kara will be up against. Why Supergirl needs The Flash’s help isn’t clear. The Silver Banshee and Supergirl have a tumultuous history: Siobhan was fired by Cat Grant, so there's likely some hard feelings. Silver Banshee has superhuman strength, agility and endurance just like Supergirl. However, she’s known for her sonic screams. She’s also able to travel through soundwaves, allowing her to teleport to some degree. Leslie, aka Livewire, has also previously appeared in Supergirl. Kara saved her from a helicopter accident, but the two of them were shocked and Leslie developed the power to manipulate electricity.

The “World’s Finest” synopsis reveals Kara will help Barry find a way back home, does this mean he didn't mean to end up in National City? This could be a case of time-travel gone bad.

Kara gains a new ally when the lightning-fast superhero The Flash (Grant Gustin) suddenly appears from an alternate universe and helps Kara battle Siobhan, aka Silver Banshee, and Livewire in exchange for her help in finding a way to return him home.

Supergirl, The Flash crossover airs Monday, March 28 at 8 p.m. on CBS.