Turn over page, captivated by Dune novel (5)
I believe the answer is:
upend
'turn over' is the definition.
(I've seen this before)
'page captivated by dune novel' is the wordplay.
'page' becomes 'p'.
'captivated by' is an insertion indicator.
'novel' indicates an anagram (letters in a new or novel order).
'dune' with letters rearranged gives 'uend'.
'p' placed within 'uend' is 'UPEND'.
(Other definitions for upend that I've seen before include "Turn top to bottom" , "Alter greatly" , "Turn upside-down" , "Tip right over" , "Invert" .)