Fled with bag of plunder (7)
I believe the answer is:
ransack
'plunder' is the definition.
('ransack' can be a synonym of 'plunder')
'fled with bag' is the wordplay.
'fled' becomes 'ran' (I've seen this before).
'with' says to put letters next to each other.
'bag' becomes 'sack' (sack is a kind of bag**).
'ran'+'sack'='RANSACK'
'of' is the link.
(Other definitions for ransack that I've seen before include "Plunder or turn upside down in search" , "Search thoroughly and destructively" , "Turn upside down in searching" , "Plunder; search ruthlessly" , "Pillage, plunder" .)