Sophia’s father was lost at sea and now she spends her days moping around Aqualand, the marine theme park her dad and uncle created. One day she witnesses an “aquanaut” breaking into the park’s research lab and shockingly discovers that inside it lives a band of four goofy sea creatures! With time, they all realize something sinister is afoot at Aqualand and they band together to free the park marine life before it's too late.