13 best serums

In the context of Political, Spies Politics, Thrillers Suspense, and Mystery Thriller Suspense books, the term "serums" doesn't have a direct or commonly recognized association. It's possible that "serums" may refer to a specific plot element, term, or concept unique to a particular book or series within these genres. However, without more specific information or context, it's challenging to provide a precise explanation.

In general, serums can be associated with various genres of literature, including science fiction and fantasy, where they might refer to fictional substances with special properties, such as enhancing abilities, altering characters, or serving as a central plot device. If you have a particular book or series in mind that involves "serums" as a significant element, providing more details could help provide a more accurate response.