The original story is set between 2138 and 2143. In this setting, human civilization has spread across thousands of star systems. Among them is an organization called the "World Welfare Work Association" (WWWA), abbreviated as "3WA", which specializes in helping various star systems solve all sorts of problems. The protagonists of the story, Yuri and Kei, are "trouble consultants" dispatched by the 3WA to different star systems. Their official team codename is "Lovely Angels," but because their work, while solving problems, often results in significant collateral damage, they are infamously known by the derogatory nickname "Dirty Pair."