Plots in Greene's novel (9)
I believe the answer is:
engineers
'plots' is the definition.
'in greene's novel' is the wordplay.
'novel' indicates anagramming the letters (letters in a new or novel order).
'in'+'greenes'='ingreenes'
'ingreenes' with letters rearranged gives 'ENGINEERS'.
(Other definitions for engineers that I've seen before include "They solve practical problems using scientific knowledge" , "Masterminds" , "professionals?" , "Contrives" , "Solvers of practical problems using scientific knowledge" .)