In an early 20th century America where soda is synonymous with cola, small-time St. Louis soda maker Charles Leiper Grigg dares to take on corporate giants Coke and Pepsi by introducing something entirely new–a clear, lemon-lime soda he calls “7-Up.” Little does he know that at the same time, two brothers in Tennessee, Ali and Barney Hartman, have concocted an almost identical soda. What started out as their personal lemon lime cocktail mixer will put them on a collision course with 7-Up when they release it to the public as “Mountain Dew.” Both will evolve into something entirely different than what they began as, but together they’ll crack the industry wide open.