Concept musical
It is generally agreed upon that in a concept musical, emphasis is placed upon style, message, and thematic metaphor rather than on the plot itself.
Thus, the show's structure is rarely cohesive or linear. Critics agree that the most defining aspect of a concept musical is its use of theme. This holistic approach to each show, which focuses on the truthful representation of the theme in every aspect of the final production, sets it apart from other musical theatre forms
Thus, the concept musical can also be defined by its structural characteristics and common staging techniques. Its songs "punctuate rather than flow out from the story," serving as a means of self-reflection for the character and acting as commentary upon the theme.
"A sense of aesthetic totality is provided not by the linear unfolding of a narrative but by the overarching staging concept, which turns the spectator's attention to the overall principle of organization in the same way that an abstract painting does."
Examples of the 'Concept Musical' Include Cats, Company and The Last Five Years.
See video:- Company is a good example of a concept musical.
There isnt a large plot but an idea or metaphor that the musical is based on.
"A musical with a story, but no plot..."
A theme, idea or feeling is the driving idea for the work rather than a plot driven piece.