Managed, with fire, to plunder (7)
I believe the answer is:
ransack
'plunder' is the definition.
('ransack' can be a synonym of 'plunder')
'managed with fire' is the wordplay.
'managed' becomes 'ran' (I've seen this before).
'with' is a charade indicator (letters next to each other).
'fire' becomes 'sack' (dismiss someone from their job).
'ran'+'sack'='RANSACK'
'to' acts as a link.
(Other definitions for ransack that I've seen before include "Pillage, plunder" , "Examine thoroughly" , "Plunder or turn upside down in search" , "Search thoroughly and roughly" , "Search, leaving no stone unturned" .)