The series tells the story of Fishtronaut, a fish in a spacesuit, similar to reverse scuba gear, which allows him to fly and breathe out of water. He is a secret agent of Secret Environmental Agency who, along with his friends Marina and Zeek, unravel the mysteries occurring in the Smiling Trees Park. They solve the mysteries with the help of a P.O.P. (Primary Objective Pod), a magical multicolored ball containing clues vital to the mission.