That fabulous detective, Freddi Fish, and her finny friend, Luther, are back to sleuth their way through another exciting adventure. Freddi and Luther fly to the tropics only to discover that the annual festival is kicked off by a trumpet blast from the one-of-a-kind Great Conch Shell and that Uncle Blenny is suspected of swiping the shell. Freddi and Luther must find the real culprit and recover the Great Conch Shell so Luther's uncle can be cleared of blame, and the Founder's Day Festival can begin!