Rescue Val in trouble taken in by wise man (7)
I believe the answer is:
salvage
'rescue' is the definition.
(I know that salvage is a more specific form of the action rescue)
'val in trouble taken in by wise man' is the wordplay.
'in trouble' is an anagram indicator.
'taken in by' indicates putting letters inside.
'wise man' becomes 'sage' (sage is a kind of wise man).
'val' with letters rearranged gives 'lva'.
'lva' inserted within 'sage' is 'SALVAGE'.
(Other definitions for salvage that I've seen before include "Collect discarded material" , "Cargo saved from wreck" , "Reclaim" , "Rescue a wrecked ship at sea" , "Retrieve goods from wrecked ship" .)