Cleo, an introverted young science prodigy from New Orleans, accidentally turns her popular older sister and the school's star lacrosse player, Molly, invisible when her class project goes wrong! Cleo, who has become accustomed to living in Molly's shadow, is forced to step outside her comfort zone and into the shoes of her older sister to take her place on the day of an important game. Meanwhile, they're up against the clock to find an antidote to reverse the effects of Cleo's experiment before Molly's invisibility becomes permanent.