The phrase "unsuspected plot" may refer to a secret scheme or plan that has gone unnoticed or undetected. Synonyms for this phrase might include "hidden agenda," "secret plan," or "covert scheme." Other related terms might include "clandestine plot," "stealthy stratagem," or "deceptive ploy." These words all carry connotations of secrecy, cunning, and possibly ill intent. Alternatively, synonyms for "unsuspected" might include "unanticipated," "unexpected," or "surprising," while synonyms for "plot" could include "conspiracy," "machination," or "maneuver." Exploring different combinations of these words can help to convey a range of meanings and nuances related to hidden schemes and subterfuge.