The Sengkang Snoopers are vacationing on the island of Sentosa, but a holiday involving this gang of sleuths really isn't complete unless there's a big mystery to decode. This time, Su Lin, Su Yang, Bus, Zizi and their loyal parrot sidekick, Kuning, pick up a curious piece of paper containing some very interesting information, including a drawing that appears to lead to hidden treasure from the Japanese Occupation. But their quest to solve a mystery lands them in mortal danger. Can the Snoopers escape from peril in time to save the day?