Isabella, the youngest (and only) daughter of King Victor Triton longs to live in the world of people and is in love with an adventurerer named Phineas, but she is forbiden to leave Danlantica, Due to her Dad's dislike of the people world. with the help of her friends, Baljeet the timid but strict crab and Gretchen her best "mermaid" friend. she sets out to make her dream come true, But little does she know she is playing into the hands of the evil sea witch Vanessa and her plot to takeover Danlantica.