Livewire

S1 E4: Kara's Thanksgiving may be ruined when she suspects her foster mother, Dr. Eliza Danvers (special guest star Helen Slater), who is coming to town, disapproves of her new role as a super hero. Also, when an accident transforms a volatile CatCo employee into the villainous Livewire, she targets Cat Grant and Supergirl. Brit Morgan guest stars as Leslie Willis/Livewire.