Shelter in rocks at foot of mountain (6)
I believe the answer is:
screen
'shelter' is the definition.
(I've seen this before)
'rocks at foot of mountain' is the wordplay.
'rocks' becomes 'scree' (rocks on the slope of a mountain).
'at' is a charade indicator (letters next to each other).
'foot of' says to take the final letters.
The final letter of 'mountain' is 'n'.
'scree'+'n'='SCREEN'
'in' is the link.
(Other definitions for screen that I've seen before include "Blind - hide from view" , "Sieve; TV display" , "cloak" , "Show; cover" , "Protect - project" .)