This is lodged when father returns with a different plea (6)
I believe the answer is:
appeal
'different plea' is the definition.
'appeal' can be an answer for 'plea' (I've seen this in another clue). I am not sure about the 'different' bit.
'this is lodged when father returns with a' is the wordplay.
'this is lodged when' becomes 'lep' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'father' becomes 'pa' (pa can mean dad or father).
'returns' says the letters should be written in reverse.
'with' means one lot of letters goes inside another.
'lep'+'pa'='leppa'
'leppa' backwards is 'appel'.
'appel' placed around 'a' is 'APPEAL'.
Can you help me to learn more?
(Other definitions for appeal that I've seen before include "Heartfelt request -- attraction" , "Bring verdict for review by higher court" , "Attraction, pleasantness" , "Charm; entreaty" , "Ask earnestly" .)