Leslie Willis is a famous, well-known radio shock jock presenter, working in the basement of CatCo Worldwide Media. When Leslie rants about Supergirl in her show, insulting her and making jokes about her sexuality, she is called before Cat Grant. Grant forbids her from continuing her slander campaign but Leslie tells her that Cat won't dictate her what to say. This causes Cat, who can't fire Leslie because of her contract, to tranfer Leslie to a traffic chopper.
On Thanksgiving night, Leslie is in the chopper monitoring the traffic. However, the weather grows into a storm quickly and the helicopter is hit by lightning, causing it to spin out of control. Supergirl arrives to save the helicopter, at first grabbing the pilot who had been blasted out of the helicopter. After delivering the man safely to the ground Kara flies back up to save Leslie, who is still inside the chopper. After preventing the helicopter from crashing into a building, Kara tells Leslie to grab her hand but while she does so, Kara is struck by lightning which is diverted into Leslie. This lightning strike throws Leslie into a coma but also gains her the ability to create electricity.
Cat and Kara later visit Leslie at the hospital. Although Cat at first acts like she doesn't care about Leslie's fate, she urges the comatose woman to wake up after Kara has left the room. Once Grant is gone too, Leslie opens her eyes which are now sparkling from electricity. She sneaks out of the hospital, entering a back alley where she accidentally shoots a bolt of lightning out of her hand. She is approached by a drunk man who starts molesting her. She ends up electrocuting him to death and after a brief moment of shock, enjoys her powers. Laughing, she transforms into electricity and leaves the alley through a street lantern.
Intending to get revenge on Cat, Leslie heads tp CatCo where Grant is working despite the holiday. Leslie draws the power from the building, causing an annoyed Cat to call Kara for aid. Once Kara has arrived, Leslie contacts both through the monitors inside Cat's building. Both are shocked to see Leslie's face but the woman claims that Leslie died in the helicopter and that the two are facing Livewire. She then leaves the screen, arriving right in front of Cat and Kara and shooting electricity at them. The two women flee into the offices and Cat remains to distract Livewire while sending Kara to get security. Kara flees from the room but returns as Supergirl just in time to save Cat from a deadly electricity blast. While Car flees from the rooms Kara fights Livewire who enters the elevator mechanism intending to have Cat drop to her death. Kara stops the elevator however.
Blaming herself for Livewire's condition, Cat later contacts Supergirl and offers to team up with her to take down Livewire. The same night, Cat uses Leslie's former radio station to lure her in, claiming that she will be waiting "where it all began". Leslie indeed turns up. Cat asks for Livewire's terms but Leslie merely states that she want's Cat's ski, quipping that there are many ways to skin a cat. This prompts Cat to state that Leslie has the wit of a Youtube comment. Furious, Leslie blasts an electricity blast at Cat but Cat manages to jump out of the way. Supergirl then appears and fights Leslie. During the fight, Leslie creates two whips consisting out of pure electricity which she uses to trap Kara. She then knocks Kara on the ground and electrifies her, wondering if she has enough power to stop Supergirl's heart. Kara then uses the rest of her strength to punch through the asphalt into a water pipe, spilling the erupting water onto Livewire and knocikng her out in an electric blast.