Betty is spending the day at the beach, where her boyfriend Fearless Freddy works as a life guard. Betty is enjoying the ocean while floating in her inflatable rubber horsey when it springs a leak. Freddy dives in to save Betty, but she goes under, where she begins to imagine she's a mermaid. At first Betty enjoys her new underwater life, swimming and singing with the other undersea inhabitants. The fun ends when a sea monster chases her. Just before the monster catches her, she wakes up, safe in Freddy's arms.