The Beatles’ film Yellow Submarine (1968) reflects conflicts between conventional society, represented by classical music, and rebellious youth culture, represented by other musical types, such as folk and pop (subsumed under the term ‘vernacular’). Taking their inspiration from the song ‘Yellow Submarine’ (Revolver, 1966), the filmmakers created a narrative for a psychedelic ‘hero’s journey’ from existing Beatles songs. This article discusses how the musical codes that symbolise different groups are used to mediate between divergent elements in both the film and contemporary society, by referring to such elements beyond the film as the Beatles’ comprehensive body of songs (which in itself forms a kind of mythology) and cultural events of the time. In Yellow Submarine, the Blue Meanies imprison Pepperland by immobilising all producers of music, whether ‘classical’ (the string quartet led by the elderly Lord Mayor) or ‘vernacular’ (Sgt. Pepper’s Lonely Hearts Club Band). The Beatles are able to free Pepperland by manipulating and ultimately uniting the musical codes – an idealistic message for the ‘real world’ to heed.