A drama involved the fleet (6)
I believe the answer is:
armada
'the fleet' is the definition.
(armada is a kind of fleet)
'a drama involved' is the wordplay.
'involved' indicates an anagram (involved can mean confusing or complex).
'drama' is an anagram of 'rmada'.
'a'+'rmada'='ARMADA'
(Other definitions for armada that I've seen before include "lot of craft" , "A great fleet, ships or planes" , "Spanish fleet sent in 1588 to escort an invasion of England" , "Navy" , "Many ships" .)