River gods rose unexpectedly in film (9,4)
I believe the answer is:
reservoir dogs
'film' is the definition.
'river gods rose unexpectedly' is the wordplay.
'unexpectedly' indicates an anagram.
'river'+'gods'+'rose'='rivergodsrose'
'rivergodsrose' is an anagram of 'RESERVOIR DOGS'.
'in' is the link.
(Other definitions for reservoir dogs that I've seen before include "Crime drama film (1991)" , "Quentin Tarantino film" .)