Thread of the story (4)
I believe the answer is:
yarn
I believe this is a double definition.
'thread' is the first definition.
(I know that thread can be written as yarn)
'story' is the second definition.
(synonyms)
'of the' is the link.
(Other definitions for yarn that I've seen before include "Fabricated" , "Exaggerated story or spun thread" , "Rambling tale" , "which could unravel?" , "A long tale" .)