Editing Big List of RPG Plots (section)

== Elementary, My Dear Watson ==

A crime or atrocity has been committed; the PCs must solve it. They must interview witnesses (and prevent them from being killed), gather clues (and prevent them from being stolen or ruined). They must then assemble proof to deliver to the authorities, or serve as personal ministers of justice.
* The PCs are working to clear an innocent already accused (possibly themselves). 
* The PCs must work alongside a special investigator or are otherwise saddled with an unwanted ally. 
* Midway through the adventure, the PCs are "taken off the case" - their invitation/authority to pursue the matter is closed (often the result of political maneuvering by an antagonist). 
* The climax is a courtroom scene or other arena of judgment. 
* The scale is highly variable for this type of adventure, from a small-town murder to a planetwide pollution scandal.