“I hear the most beautiful sound in the world,” says Dr. Bruce Means. He is referring to the call of a toad that he and his expedition team – North Face Climber Mark Synnott and National Geographic contributing photographer Joe Riis – traveled a long way to find. All the way to the tops of the Tepuis of South America. The Islands in the sky. Means has a hypothesis that he calls a paradigm shift in all of the work up until now concerning the age of the species living on Tepui summits as well as the age of the Tepuis themselves. This little toad is the missing link. In this short film, the team braves the elements and first time repels into crevices in search of this illusive pebble toad. If they find this toad, will they make it back out of the crevice? The expedition to the Tepuis was made possible by National Geographic Expeditions Council.