Moves chess pieces, with son suffering checks for crazy plans (7,2,5)
I believe the answer is:
castles in spain
'plans' is the definition.
(I have seen 'Unrealistic plans' mean 'castles in spain' so perhaps 'plans' could also mean 'castles in spain')
'moves chess pieces with son suffering checks for crazy' is the wordplay.
I cannot really understand how this works, but
'moves' could be 'castles' (castling is a kind of moving) and 'castles' is located in the answer.
'son' could be 's' (genealogical abbreviation for son) and 's' is found in the answer.
'suffering' could be 'inpain' (I've seen this in another clue) and 'inpain' is located in the remaining letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
(Other definitions for castles in spain that I've seen before include "Unrealistic plans" , "pipe dreams" , "Maybe Segovia keeps" , "Wild dreams" , "being a dreamer's goal" .)