The most common and most likely answer to this crossword clue is the 10 letter word CONSPIRACY
I've seen this crossword clue in The Guardian
C
O
N
S
P
I
R
A
C
Y
More clues leading to the result CONSPIRACY
- Plot against second main crime
- Plot theft at sea with criminals
- Plot linking kids to the main crime
- Hoodwinks detective with naughty piece of intrigue
- Votes against infringement of copyright plot
- Tory’s buccaneering plot
- Plot the crime of a criminal?
- Those against crime plot
- Tories take on major crime cabal
- Plot links prisoners to criminal activity
Buddy explains!

The straight part
We know that "Plot" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case plot = conspiracy.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CONSPIRACY mean?
CONSPIRACY noun- The act of two or more persons, called conspirators, working secretly to obtain some goal, usually understood with negative connotations.
- An agreement between two or more persons to break the law at some time in the future.
- A group of ravens.
- A group of lemurs.
- A situation in which different phonological or grammatical rules lead to similar or related outcomes.
- (by ellipsis) A conspiracy theory; a hypothesis alleging conspiracy.
- To conspire.