The Superhero Twins are a set of five-year-old identical twin sisters named Haylee and Kaylee who live at an all-girls superhero preschool. Both of them always wear rubber bodysuits, rubber gloves, rubber boots, superhero capes and superhero masks that hide the top half of their faces. Their superhero names are Whirlwind Girl and Lightning Girl. They share their preschool with their teacher Ms. Olive, whose superhero name is Frost Girl, and their three friends Tessa, Camille and Penelope, whose superhero names are Supersonic Girl, Flame Girl and Plant Girl.