“Worlds Finest” is episode eighteen of season one of Supergirl.
In the previous episode, “Manhunter”, Hank and Alex had been arrested and were being carted off to something dodgy called Project Cadmus. Kara revealed to Lucy – who was investigating the DEO with a Colonel Harper – that she was Supergirl. Which Lucy felt explained a lot. Lucy had agreed to help Kara and the two them rescued Alex and Hank. Hank messed with Colonel Harper’s mind – not as destructively as when he did it before in “Childish Things” – and Harper resigned from leading the DEO. Putting Lucy in charge.
Siobhan is currently at the DEO being examined by Dr Hamilton. At the end of the last episode, Siobhan was standing on a roof, drinking and talking to Winn, when she accidentally fell off. And screamed all the way until she didn’t splat into the ground. Winn and Kara are watching as Siobhan is examined; Siobhan is not a Fort Rozz escapee and Kara doesn’t recognise her from Krypton. She points out that Krypton was a big place – it was a planet, after all – and they didn’t all know each other.
Winn says that Siobhan fell four stories and doesn’t have a scratch on her, and the only person he knows that can do that is Kara (plus all the other Kryptonians, but he probably isn’t personally acquainted with any of them). Kara suggests that Siobhan can be National City’s new hero; Supergirl’s attempts to win back the public trust after going off her head thanks to Red Kryptonite in “Falling” are not working. Supergirl apparently helped a family assemble an IKEA table (IKEA: So hard to build you need a superhero to help) last night but it’s still not enough. Perhaps she’s trying a little too hard. Winn tells Kara it wasn’t her fault; she was poisoned. She replies that people don’t know that.
Dr Hamilton finishes examining Siobhan and tells Winn and Kara that Siobhan didn’t splat because she emitted a high-frequency sound wave that cushioned her fall and pulverised her cement. She’s not an alien either; she’s human. So, no-one knows why Siobhan has powers and she tells them thanks for nothing. On the way out, Siobhan speaks to Winn and says he told her that these people could help. And since when did he know Supergirl? Winn replies he would have told Siobhan about Supergirl; when asked when, he says maybe if they went on an actual date.
Siobhan seems to hear something at this point and says she has to go. She sees a cell where Livewire, imprisoned since the episode of the same name, is being questioned by Lucy. Lucy says to Livewire that people in National City have been experiencing electrical imbalances in their brains and that Livewire is the only person they know capable of things of such magnitude. Livewire states she isn’t behind it, and besides, she’d rather fry Cat Grant and Supergirl.
At CatCo, Cat opens a box of cupcakes in front of Kara. She tells Kara that cupcakes don’t last long, and if you don’t grab one they will be snapped up. And, in case Kara isn’t grasping it, Cat is talking about Kara’s, non-existent, relationship with James. Cat suggests Kara read a book of hers – which she admits isn’t her best work – essentially saying that the best way to chase James is not to chase him. Instead, to make him jealous.
Siobhan is in the street when she seems to hear and see something so heads to CatCo. Winn tries talking to her but Siobhan is not responding. Siobhan walks over to Kara’s desk and blasts Kara out of the window with her voice. As Kara is falling to the ground, a blue portal opens on the street below and a blur speeds out of it, up the building and grabs Kara as she falls. The blur – the Flash, Barry Allen; this is a crossover episode with The Flash – whisks Kara out into the countryside.
Kara is on fire when the Flash stops, which he tells her – and notices she doesn’t seem very bothered about. Kara tells him she didn’t need help; he responds that she fell from a skyscraper and would have gone splat if he hadn’t caught her. Kara replies that she needs to get back to the city, and flies off. Which Barry comments is a new one.
Barry runs after Kara and stops in front of her. He wants to know who she is; she tells him she’s Supergirl. The name means nothing to him. Barry says he caught her and ran out of the city. Which he didn’t mean to do; he’s been working on his speed. Barry is wearing a tachyon device, which he was testing at the start of “Versus Zoom”. Kara doesn’t know who the Flash is, which seems odd – both are quite famous but neither has heard of the other. Kara doesn’t know any of the other superheroes he mentions either. At this point Barry realises what’s going on. He introduces himself by his proper name and says he’s on the wrong Earth. And needs help.
Back at CatCo, in Kara’s secret office, Barry cannot find S.T.A.R. Labs – Central City exists – or any of the people who work there. Who would be able to help him. Winn and James arrive and Kara introduces Barry as being from another universe. Winn thinks that’s cool and mentions the theory of the multiverse.
Winn is taking this all in stride and Kara comments that she still can’t believe Barry is from another planet. Winn points out that Kara’s an alien. Which Barry asks to be confirmed. He thinks that’s cool and asks if there are other aliens on this Earth. Barry explains what happened and Winn understands it and that he’s stuck. All in all, a rather complicated introduction. James is less than happy and, after Kara and Barry leave, Winn tells James he’s jealous. James denies this.
Kara, James, Winn and Barry end up in Cat’s office. She has a picture of the Flash racing up the building and says that Supergirl has competition. When told that it’s not necessarily a competitor, she asks if sidekick would be preferred. Ally and partner are suggested instead. Cat wants a clear picture of the speedster and tells Kara that lots of people want to know what happened to her. But to speak to no-one, for she’s Cat’s. Cat also wants to name the speedster; she doesn’t like Barry’s suggestion of the Flash and goes with the Blur.
Siobhan goes to see her aunt, Sinead, and tells her she’s got a problem. Her aunt says she can hear it, the calling and the whispering. And that it’s the banshee. She asks Siobhan if she’s ever wondered why all the women in their family are so… unlikeable. Sinead says the family is cursed by a banshee before they left Ireland. It is triggered whenever anyone wrongs them. Siobhan asks if there’s any way of stopping the curse. Apparently she ne3eds to kill the object of her anger; if she doesn’t, the power grows. Siobhan asks how she can kill Kara if she’s got a superhero protecting her. Light bulb moment. Get someone to help who wants Supergirl dead. So Siobhan breaks Livewire out of the DEO. From a distance. With her voice.
Kara gets a call from Lucy about Livewire’s escape and tells Cat she needs to leave. Cat says she isn’t fleeing; she beat Livewire once and can do it again. Then admits she had help. And will have it again. National City may have lost faith in Supergirl but Cat hasn’t.
Barry likes the DEO’s facility – which he examined at superspeed – and wants a photo with Kara’s pod. Winn and he are hitting it off as well. James is definitely getting jealous. Lucy notices, as does Cat – who tells Kara to keep doing it. Kara also needs Barry’s help dealing with Livewire and Siobhan – or Silver Banshee.
On an unrelated matter, the episode ends leading into the next one, “Myriad”.