Eve perhaps is in on the plot (8)
I believe the answer is:
gardener
'eve' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'perhaps is in on the plot' is the wordplay.
I cannot quite understand how this works, but
'plot' could be 'garden' (garden is a kind of plot) and 'garden' is found within the answer.
The remaining letters 'er' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for gardener that I've seen before include "One grows" , "Eg, Capability Brown" , "Jesus was mistaken for" , "someone in bed" , "He tends flowers and shrubs" .)