Main character has to move slowly (4)
I believe the answer is:
inch
'move slowly' is the definition.
(I've seen this before)
'main character has' is the wordplay.
'has' says the answer is hidden in the clue.
'INCH' is hidden within 'main character'.
'to' acts as a link.
(Other definitions for inch that I've seen before include "Crawl; imperial measurement" , "Progress slowly" , "One 63,360th of a mile" , "Two point five four cm" , "Islet (Scots); twenty-five.four mm" .)