The story of a young girl, Ariel, who befriends a legendary sea monster, Ug Wug, while on summer vacation with her mother. When Ariel stumbles upon Ug Wug, scared at first, she comes to believe that she might be able to befriend the monster, which she does with her gentle personality and lots of blueberry jam sandwiches. Ariel is not the only one who knows of Ug Wug's existence; she shares this secret with an old family friend Mr. Van Der Zee, and monster researcher Kwimu; all three wear necklaces made from one of Ug Wug's scales which can only be found by those whom Ug Wug wants to find them. But when Ug Wug is spotted by a shrewd greedy businessman, Mr. Green, who is determined to capture and make millions off him, Ariel's only choice to save Ug Wug may be to say goodbye forever!
