AllMovie

During a family day at the beach, Dee Dee tries out her new mermaid swimsuit while Dexter gets in his submarine in order to record whale music. Dee Dee finds a white whale pal, and tells Dexter to buzz off so she can play with him. But little does she know that a deranged sea captain is hunting the white whale; when she intervenes, she is mistaken for a mermaid and is captured. It's up to Dexter and the whale to save her. (Original air date: September 24, 1997.)