It finally happened! The Flash came to National City and joined Supergirl in the fight against Livewire and SIlver Banshee in “World’s Finest.” For a quick catch up with The Flash, Barry Allen has been working on getting faster, so he can defeat Zoom. He arrives on another Earth where he meets our resident hero, Supergirl.

Siobhan Smythe all of a sudden broke out her banshee cry last week to save herself from a fall off of the roof of a building. She and Winn are both worried about her health and take her to the DEO. Winn assured her that they would be able to help, but no one can seem to find anything wrong with her. She’s not an alien which means she definitely can’t be a Fort Rozz escapee. So what is she?

Siobhan starts getting headaches and hears someone calling out to her. It seems these new powers are making her more evil than ever. She goes straight to CatCo to confront Kara. Using her banshee cry, Siobhan forces Kara out the window. Even though she’s Supergirl, The Flash comes in to save her. He runs her out into the middle of nowhere, but Kara says she needs to get back. They each reveal themselves as superheroes, but they have never heard of one another. It’s clear to Barry that he is on another Earth. Which Earth did he go to? Will we ever find out?

“Worlds Finest” — Kara (Melissa Benoist, left) gains a new ally when the lightning-fast superhero The Flash (Grant Gustin, right) 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, on SUPERGIRL, Monday, March 28 (8:00-9:00 PM, ET/PT) on the CBS Television Network. Photo: Michael Yarish/Warner Bros. Entertainment Inc. © 2016 WBEI. All rights reserved.

Meanwhile, Siobhan is trying to figure out what’s wrong with her. She goes to see her aunt who tells her that her family is cursed. They get cursed when someone has wronged them. In order to break the curse, Siobhan must kill the one who wronged her. Her aunt warns that in doing this, she will lose her soul. Siobhan is now on a one track mind to take out Kara Danvers. After overhearing Livewire at the DEO, Siobhan decides to partner up.

Barry agrees to help Supergirl with Livewire and Silver Banshee, while they figure out how to get him back to his Earth. When he meets Winn and James, they have slightly different reactions. Winn is very excited that Barry is from another universe. James, on the other hand, can’t understand how Barry has his powers. My favorite scene is when Barry brings everyone ice cream in a split second. Kara is so giddy and exclaims, “YES!” Barry and Kara are obviously excited to show off their powers to someone else who gets it.

Silver Banshee and Livewire start to wreak havoc on National City, but alas, The Flash and Supergirl are here. Barry says, “Let’s settle this like women.” Kara gives him a funny look, but he just says, “What? There’s more of you guys than me.” It may be small, but I love how they give a nice nod to strong women on this show. The heroes divide and conquer, and Supergirl saves a helicopter from Livewire’s electricity, but it affects her more than she would have hoped. Supergirl is down for the count, but the people of National City are ready to come to her rescue for once. Firefighters douse Livewire with water to short circuit her powers. In turn, Livewire accidentally zaps Silver Banshee, and they are both defeated. The firefighters tell Supergirl that it was their turn to save her.

“Worlds Finest” — Kara gains a new ally when the lightning-fast superhero The Flash suddenly appears from an alternate universe and helps Kara battle Siobhan, aka Silver Banshee (Italia Ricci, left), and Livewire (Brit Morgan, right) in exchange for her help in finding a way to return him home, on SUPERGIRL, Monday, March 28 (8:00-9:00 PM, ET/PT) on the CBS Television Network. Photo: Robert Voets/Warner Bros. Entertainment Inc. © 2016 WBEI. All rights reserved.

Well now that the day is saved, it’s time for The Flash to go home. Barry thinks that if Supergirl can use her speed to help launch Barry, he can get back to his Earth. Let’s just hope this works out. While we didn’t really get to see who would win in a race, we got to see both The Flash and Supergirl running, and Supergirl launches the Flash through a breach. Guess we will have to tune in to the Flash to see how that works out.

Is there anything better on Supergirl right now than Cat Grant giving Kara advice on her love life? Cat Grant compares Kara’s love life to a box of cupcakes. She tells Kara that she needs to make a power move to get James to notice her. Cat quotes herself in a novel she wrote in the 90s and tells Kara, “Shine your light and let him come to you.” Of course, Cat isn’t actually proud of her book, but it did get her on Oprah.

When Barry, Kara, Winn, and James are in Cat’s office, Cat sees that James might be jealous of Barry. Kara tries to play it off like Barry is just a friend, but Cat knew all along that he was The Flash. Kara is oblivious to James’ jealousy until Cat points it out. Winn and Lucy, on the other hand, caught on right away. James tried to play it cool, but everyone was trying to push him toward Kara.

Kara finally gets to confront James about her feelings, and she ends up rambling about infinite earths (we hear you DC). He seems confused, so she says that she’s much better at doing. Kara kisses James, and when she steps back he has a blank look on his face. She is clearly very nervous and doesn’t know what to think of his non reaction to their kiss. All of a sudden, James walks out the door along with everyone else in National City. It looks like the myriad is underway, and Nan couldn’t be happier. He says menacingly, “For you Astra, first, National city, then the Earth will belong to us.”