Supergirl fans were treated to a crossover between The Flash and their hero on the Monday night episode with Grant Gustin guest starring alongside Melissa Benoist.

‘SUPERGIRL’ Season 1, Episode 18 RECAP

The episode kicked off from where last week’s left off with Siobhan’s rooftop discovery that she has a super scream. Winn takes her to the DEO to have her examined and tested. only to find out that she is just superhuman and not super hero. Yet. Meanwhile, Kara is still trying to win back the trust and respect from National City.

After Siobhan leaves the headquarters, she runs into Livewire who is the enemy of Cat Grant. She then starts to develop very strong headaches and visions that makes her go back to headquarters. When she sees Kara, she deploys her sonic scream to blast her out a window and Winn is shoved across the room. As the hero is falling, she can’t save herself or she will blow her cover, but then she is saved by a mysterious blur in a red suit: the Flash. “The who now?” Kara says, hilariously. As her clothes catch on fire due to the high speeds, she jumps from his grasp and flies back to make sure everyone is ok, thus blowing her cover to the new hero. The two size each other up and realize they have the same enemies and friends.

“Hi, I’m Barry Allen. I’m the fastest man alive. I also think I’m on the wrong Earth and I’m gonna need your help.”

Once they find out who the other is, they are eager to help the other out. Kara introduces Barry to her team which makes James a little jealous of the new superhero.

Meanwhile, Siobhan finds out her powers come from a family curse called “the banshee,” which won’t leave her until she kills the person who wronged her by using her scream, which also comes at the cost of her soul. This means that Kara is Siobhan’s number-one target but since Kara is under the “protection” of Supergirl, she finds a partner in Livewire.

When the news comes that Livewire is making a ruckus, Supergirl and the Flash work together to stop the culprit but are blindsided by Siobhan who now calls herself Silver Banshee and has a full makeover. The two heroes retreat back to CatCo to regroup and come up with a plan. Kara confesses to Barry about her epsiode with Red K and Barry replies with a few encouraging words. “When you can solve problems with brute strength or amazing speed, it’s humbling to know there are things outside of your control.”

The following day, the two heroes develop a plan to take down Livewire and Silver Banshee but are once again caught off guard when the evil duo kidnap Cat. While holding Cat hostage at a park, they challenge Supergirl to come stop them before they kill her. The two heroes are off again. While trying to negotiate, Livewire blasts Flash and moves onto a news chopper. Kara then throws herself in front of the chopper in front of a huge crowd of onlookers. As the hero lays on the ground unable to move after the huge blast, the crowd gathers around her to protect her.

“It was our turn to help you,” the crowd says, including firefighters.

With Livewire and the Silver Banshee caught and the city is safe, the Flash heads back home.

The end of the episode focuses on James’ growing jealousy of Kara’s friendship with Barry. He decides to drop by her apartment and do what fans have been waiting for all season: kiss Kara. When they detach, James says nothing and walks away without a word. All of National City steps outside simultaneously, as the streets are full of mindless people walking somewhere in unison. Kara doesn’t know it yet, but Non has made his move, and he’s wielding a device that affects all of National City.

Unfortunately, Supergirl isn’t in the lineup for a second season just yet. CBS has yet to confirm that it will get a second season. “We have five new shows on this year,” CBS Corp. CEO Les Moonves said of the newest shows. “Of those five, I believe all five of them will be renewed, and we own four of them.”

Catch the next Supergirl Monday night at 8 p.m. EST on CBS.