The plot revolves around two heirs, Prince Frederick (Barry Gibb) and his brother Prince Marmaduke (Maurice Gibb), and their dying father (Frankie Howerd). On his death bed, The King orders his kingdom divided into two halves, the Kingdom of Jelly and the Kingdom of Cucumbers. Before the king even dies, Prince Frederick declares himself "King of Cucumbers" and Prince Marmaduke becomes the “King of Jelly”. The film intersperses comedy sketches with Bee Gees songs plus performances by Lulu and Blind Faith with cameo appearances.
