Unrealistic plan to broadcast Saint-Saëns clip (7,2,5)
I believe the answer is:
castles in spain
'unrealistic plan' is the definition.
(phrase meaning an impossible goal)
'broadcast saint-saens clip' is the wordplay.
'broadcast' indicates an anagram.
'saint'+'saens'+'clip'='saintsaensclip'
'saintsaensclip' with letters rearranged gives 'CASTLES IN SPAIN'.
'to' acts as a link.
(Other definitions for castles in spain that I've seen before include "Wild dreams" , "Iberian keeps" , "Continental chessmen?" , "Unrealistic plans" , "Unrealistic hopes involving" .)