The popular KiKA presenter Checker Tobi returns to the big screens: This time it's all about a mysterious, locked treasure chest to which only Marina, circumnavigator and Tobi's best friend from childhood, has the key. But where is it? The search for it takes Tobi to Vietnam, to the largest cave in the world, across the stormy South China Sea, to horse herders on the Mongolian steppe and to indigenous people in the Amazon rainforest of Brazil.