The Supergirl / The Flash crossover event delivered everything fans wanted of the special Supergirl episode. The crossover episode was easily the best Supergirl episode to date, striking just the right tone and just the right mix of humor, drama, and action. Titled “World’s Finest,” the episode found Melissa Benoist as Kara/Supergirl and Grant Gustin as Barry Allen/The Flash participating in the perfect “meet cute” and teaming up to take down Silver Banshee and Livewire. Benoist and Gustin have terrific chemistry and fans can only hope there will be more pairings of these two in future episodes.
Airing on March 28, 2016, the much-anticipated Supergirl and The Flash crossover started off immediately after the events in last week’s episode. Siobhan is being examined at the DEO after surviving a fall that should have killed her. Winn’s as supportive as possible, trying to help her figure out what’s wrong but all that can really be determined is that a high frequency sound wave pulverized the cement and cushioned her fall. Winn and Kara can’t figure her out, but Kara has problems of her own as she’s still super frustrated she can’t win the city back. Winn thinks the frequency thing means the girl he’s dating is an alien, but she’s not. Her DNA is normal. Siobhan’s understandably upset no one can figure out what happened, and she’s mad Winn didn’t tell her he knows Supergirl. But ever the nice guy, Winn says he’ll figure it out and stick by her no matter what. Just then she hears a high-pitched noise and sets off in a trance. She passes by Livewire’s cell and hears her telling Lucy Lane (Jenna Dewan Tatum) that Cat Grant, Supergirl, and Kara are on her hit list.
Kara makes it into the office and Cat (Calista Flockhart) has cupcakes which Kara wants but Cat thinks she’s just too afraid to step up and take one. Cat’s comparing cupcakes to Kara’s non-existent love life, with Kara confiding she needs help figuring out how to handle James (Mehcad Brooks) and Cat suggests the best way to go after James is not to go after him at all. The same goes for cupcakes as Cat thwarts Kara’s grab for one.
On the street, Siobhan is still hearing the loud buzzing in her head and can’t figure it out. It’s painful and incapacitating, but then she has what looks like a moment of clarity and heads to CatCo. Winn warns her Cat will kick her out but she ignores him, saying, “You ruined my life, Kara Danvers,” and sending her flying out the window. Fortunately, The Flash races in and saves her before she crashes. Unfortunately, her shirt’s on fire by the time he sets her down somewhere outside the city. Barely thanking him, she takes off back to the city but quickly returns in her Supergirl outfit and they engage in a very awkward introduction. She doesn’t know who The Flash is; he doesn’t know who Supergirl is. Barry (Grant Gustin) even tries name-dropping Arrow, Zoom, Black Canary, etc., etc. with no luck which leads him to believe he’s on the wrong Earth and needs her help since she has no idea who he is and he has no idea how he got there.
Kara lets Barry use the computer and he finds they have a Central City but no S.T.A.R. Labs on this Earth which means he can’t get home. In comes Winn and James Olson and Kara introduces him as Barry from another universe. In turn, Barry learns Supergirl’s an alien and wants to know if there are other aliens on this Earth. The “this Earth” comment confuses James so Barry maps out a drawing to explain other Earths, and Winn totally geeks out. He also explains that he’s the fastest man on the planet and proves it be racing out and getting them each ice cream cones. They decide this is pretty cool and Winn wants to know if he can just pop through universes. He can’t and is sort of stuck here. Because of his metabolism Barry needs 10,000 calories a day but he’s met his eating match in Kara. Being a huge eater, she’s more than willing to head out to get donuts and other munchies. When they leave, Winn teases James about the way he looks at Kara, comments that James does his best to deflect.
They head back to CatCo where Cat tells Kara she’s the all over the news now and that Supergirl has a rival hero in town. Barry’s sort of excited about being a rival hero but slightly less pleased when he’s referred to as a sidekick. Cat looks at Barry, James, Winn, and Kara and delivers the best line of the entire Supergirl series: “All four of you standing there doing nothing, you look like the attractive yet racially diverse cast of a CW show.” All business, Cat wants a picture of the speedster and she nicknames him The Whoosh or The Red Streak, and Barry suggests The Flash. “Sounds like someone whose only superhero power is jumping out of an alley in a trench coat,” replies Cat, deciding the speedster’s name will be The Blur.
Siobhan visits her aunt and asks for her help. Unexpectedly, her aunt asks if she hears the Banshee calling to her. Then she explains all the women in their family are cursed by a Banshee and that the curse is triggered when someone wrongs her. To make it stop, she has to kill the object of her anger. If she doesn’t, her voice becomes a weapon. Her scream will decimate her target, but she’ll also destroy her soul at the same time. Siobhan really wants to kill Kara but she’s got a superhero protecting her, which means the enemy of her enemy is her new partner and off she heads to free Livewire who, as we all know, has a hit list that almost matches Siobhan’s.
At work, Kara learns Livewire has escaped and immediately starts planning how to keep Cat safe. She wants to send her away, but Cat believes Supergirl will keep protect her. Kara rushes off to tell Barry about Livewire (he says they have a rogue named Blackout) and that she wants to kill Miss Grant. She tells him National City needs The Flash and after he helps her, she’ll help get him back home. “What do you say? Partners?” asks Kara. “Partners,” replies Barry. Meanwhile, James is pouting about Kara paying so much attention to Barry and asking for this stranger’s help.
The Flash heads down to the DEO where Barry geeks out (there’s a lot of that this episode) over the facility and over Supergirl’s spaceship. He wants a photo with it but he’s told it’s off-limits. The team doesn’t want him there, but Supergirl explains he’s a metahuman there to help that. Lucy Lane’s not impressed, but that doesn’t stop Barry from wanting to check out their crime lab.
Meanwhile, Livewire grabs a beer and meets with Siobhan at an empty warehouse. Siobhan reveals she’s the one who broke her out, demonstrating her scream and breaking windows. She needs Livewire’s help killing Kara and they need to team up, with Livewire saying they’ll be like an evil Taylor Swift squad. Livewire agrees but only if Siobhan gets a better outfit.
Lucy calls out James for sneering at Kara as she works with Barry. Lucy tells him not to hold back with Kara because of her, explaining they just aren’t ever going to work out. Kara interrupts by yelling they found Livewire – or actually Barry did which irritates James even more. Barry asks about the plan but Supergirl doesn’t really have one other than to overpower them physically. Although Winn and Barry, once again, geek out over a plan to build something, Kara just wants them to go get Livewire. They race to the abandoned warehouse where she’s been seen, with Supergirl claiming 1st place although The Flash says he circled the block to make sure it was safe so “technically” he let her win. They don’t see Livewire until she zaps them. Barry uses his speed to run circles around her, but building up the electricity was exactly the wrong thing to do. She zaps The Flash and then Silver Banshee screams, making Supergirl’s ears bleed. In her new skeleton-inspired costume, Silver Banshee teams up with Livewire to take out Supergirl. Supergirl and The Flash revive enough to use a cold blast and mini-tornado on Livewire and Silver Banshee long enough so they can live to fight another day, opting to take off and actually make a plan instead of winging it like they did this time.
Kara and Barry regroup, and Kara apologizes for rushing in without a plan. She also admits she did horrible things a few weeks ago because she was exposed to something that altered her. She’s now making stupid mistakes because she wants to prove herself to the city. Barry offers advice (just as Arrow did back in the day), telling her she needs to slow down and stop trying so hard to get back in their good graces because some things are out of her control. “Believe me, when you stop trying to force the solution it will happen on its own,” says Barry. Kara tells him she’s really glad he’s there but she’s sorry he’s locked out of his world.
Back at CatCo, James and Cat are both looking for Kara but Winn doesn’t tell either where they are. Livewire and Silver Banshee show up, and Cat says she sees her ex-minions have united. Cat suggests they call Norma Rae to see how it’s really done. Winn tries to get Siobhan to stop the attack but she says this is who she is now. He tries to convince her she’s just confused and that she doesn’t have to cross this line, but Siobhan says she’s good as is and uses her crazy voice to knock everyone down.
Barry tells Kara about Pied Piper – Kara loves the nickname – and Lucy tells them the evil duo now has Cat. A video message demands Kara and Barry go to National City Park if they want to save Cat, and Barry and Supergirl race off after Barry first confirms there are Three Musketeers on this Earth.
Livewire and Silver Banshee guard Cat on a bench while they wait for The Flash and Supergirl. Cat asks for the evil duo to let her go because her boys need her, and just then in pops The Flash and Supergirl, with Barry saying, “What do you say we step away from the nice lady and settle this like women?” When Kara throws him a look, Barry says, “What? There’s more of you guys here than me.”
Silver Banshee screeches but the earplugs work and have no effect. Livewire uses her electricity but Barry’s handling it. Supergirl releases Cat from her handcuffs while Barry and Livewire fight on top of a nearby building. Supergirl and Silver Banshee go at it, and Livewire suddenly spots a helicopter and tries to use lightning to bring it down but Supergirl flies up to block it and keep the crew safe. The townspeople watch as she saves them but is hurt, falling to the ground. They move to shield Supergirl, blocking Livewire and Silver Banshee from attacking. While heroic, the move doesn’t work because Livewire doesn’t really care about collateral damage. Fortunately for the brave citizens of National City, Silver Banshee still has her humanity and turns on her partner-in-crime, effectively ending the evil dynamic duo who are then hosed by firefighters. “Supergirl, it was our turn to help you,” says one handsome, hunky firefighter as he helps Kara stand up.
Back at CatCo, Kara asks for time off to say goodbye to Barry and Cat asks her if she means The Flash. Cat said it was obvious Barry was The Flash and that she can always spot something unusual in her midst.
It’s time for The Flash to try and return to his Earth, but he needs Supergirl to throw him in order to send him home. They exchange Girl of Steel and Scarlet Speedster comments and admit they’re going to miss each other, and Barry tells her he thinks it’s very cool she’s an alien. He also thinks James thinks she’s super cool and advises that she should speed things up with him. Going slow is good advice for a superhero, but not good advice for a relationship. And off they go!!! Supergirl launches him forward and after he’s gone she heads home.
James arrives at her door and asks about Barry and she thinks he made it home. They stumble and fumble over their words and Kara says she wants to talk about infinite Earths. She says Barry told her about them, which causes James to flinch, and she uses Barry’s explanation to say that maybe there’s a chance they could be together. James asks what she’s saying and she says, “No more saying. I’m so much better at doing,” followed by the long-awaited kiss. She asks if it was good and he doesn’t reply. She’s confused as he turns and leaves her place without saying a word. She follows him into the hall and sees others just mindlessly walking. The city is under attack…