Pet doesn't start mad return to city (9)
I believe the answer is:
amsterdam
'city' is the definition.
(Amsterdam is an example)
'pet doesn't start mad return' is the wordplay.
'pet' becomes 'hamster' (I've seen this before).
'doesn't start' means to remove the first letter.
'mad return' becomes 'dam' (I am not sure about this - if you are sure you should believe this answer much more).
'hamster' with its first letter taken off is 'amster'.
'amster'+'dam'='AMSTERDAM'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for amsterdam that I've seen before include "Dutch capital" , "Mam stared awkwardly at the Dutch city" , "Western European city, a major diamond centre" , "place of canals" , "Dutch port" .)