The thread of the tale! (4)
I believe the answer is:
yarn
I believe this clue is a double definition.
'the thread' is the first definition.
('yarn' can be a synonym of 'thread')
'the tale' is the second definition.
(synonyms)
'of' is the link.
(Other definitions for yarn that I've seen before include "Rambling story" , "that'll keep you in stitches?" , "Rope" , "Exaggerated story or spun thread" , "Tale; weave" .)