A prison truck from Metropolis is entering Gotham City. The prisoner is Livewire, on her way to experimental treatments at GothCorp that may succeed in returning her to normal. However, the truck drives past a recent road accident, where a power cable has fallen to the ground. The truck passes close enough to let Livewire absorb its power, and escape. Batgirl is driving the Batmobile, searching the city for Livewire. Over the radio, Batman tells her he'll be back in Gotham in two days, and will try to get her some backup in the meantime. Batgirl isn't worried, assuming Livewire is already heading back to Metropolis... until she spots Livewire skimming along some power cables. Livewire spots Batgirl and immediately lands on the Batmobile's hood, sending current through the body that shocks Batgirl. In Metropolis, Kara is house-sitting for Clark Kent while he's out of town. On the phone with her foster mother, she reports that, much to her disappointment, crime in Metropolis is slow that week. Then Batman telephones the apartment, asking for Clark Kent. Without giving his name, Batman advises Clark that Livewire is loose in Gotham, and if Kent wants to "get on top of the story," he should head there, immediately. With Superman gone, Kara immediately assumes her Supergirl outfit and flies to Gotham. Batgirl manages to escape the Batmobile by ejecting, landing safely in Gotham Park. Livewire lands in the park and begins tossing electric blasts, but all Batgirl can do is dodge acrobatically. Livewire finally nails her with one and is about to shock her to death when Supergirl appears, grabs Batgirl and flies off. But another blast from Livewire drops them both out of the sky. Livewire is about to kill both of them, but then her power runs down. She disappears. "Welcome to Gotham," Batgirl says, by way of greeting.

As the GPD mobilizes to capture Livewire, Harvey Bullock reproaches the girls for letting her get away. He is in the unusual position of asking for Batman's whereabouts, and telling the two "amateurs" to stay out of their way.

Supergirl fumes, but Batgirl encourages her that together they are more than a match for Livewire. In a defunct zoo garden, Poison Ivy and Harley Quinn are sharing hideout. Harley is itching to get out and have some fun, but Ivy says they can't draw Batman's attention until they have "an edge." Then Livewire appears out of their toaster and proclaims, "Ladies, meet your edge!"

The new villainess team goes to a closed shopping mall, to loot the cash machines and raid the stores. Batgirl and Supergirl arrive and catch Livewire alone, managing to incapacitate her with a coating of electric-resistant silicate dust. However, Harley and Ivy join in. Harley knocks Batgirl into an open elevator, while Ivy tosses plant spores that sprout vines powerful enough to give even Supergirl pause. While Harley helps Livewire to their getaway car, Supergirl finally frees herself of the vines. Ivy tosses another set at Batgirl, but Supergirl incinerates them with her heat vision – inadvertently releasing a poisonous cloud of pollen that forces Supergirl to grab Batgirl and fly her to safety, while the villainesses escape.

To celebrate, Harley drags Ivy and Livewire to the Iceberg Lounge, but Livewire can't be near so much water. As they argue, Penguin appears and orders them to leave. Smiling, the girls suddenly fuse into a close-knit team and start wreaking havoc. Later, Batgirl and Supergirl approach a frazzled Penguin at the empty Lounge, and Penguin mentions hearing rumors about where Ivy and Harley's hideout is...

They enter the zoo, Batgirl carrying a tank of silicate to incapacitate Livewire. But Ivy's plant-based warning system tips off the villainesses, and Ivy quickly relieves Batgirl of the tank. Comically, Harley knocks herself out by firing her spring-loaded boxing glove at Supergirl from behind – where it bounces harmlessly off Kara's head, shoots back and hits Harley. Ivy wrestles Supergirl to the ground with her plants, while Livewire attacks Batgirl. Batgirl shields herself from the electric blasts with a garbage pail lid. Vexed, Livewire fires a souped-up blast, which ends up setting Ivy's plants on fire. Desperate to save her "babies," Ivy releases Supergirl and climbs to a water tower, releasing a stream of water that puts out the fire, but shocks Livewire unconscious. The tower then collapses, knocking Ivy out. Later, at Barbara's apartment, the two super-heroines have treated themselves to a makeover and a pint of ice cream each, as they watch coverage of their success on the news. When interviewed, Bullock grudgingly admits that the two heroines have "some potential." Considering the source, Barbara and Kara recognize high praise, and share a resounding high-five.