Music drama Ted worked on (5)
I believe the answer is:
opera
'music drama' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for opera that I've seen before include "La Traviata or Tosca, say" , "Staged event" , "Billy Budd, for instance" , "Music and drama production" , "Eg, The Magic Flute" .)