Great, extremely labyrinthine story (5)
I believe the answer is:
fable
'story' is the definition.
(fable is a kind of story)
'great extremely labyrinthine' is the wordplay.
'great' becomes 'fab' (short for fabulous).
'extremely' says to hollow out the word (remove centre letters) (only the extremes of the word are used).
'labyrinthine' with its centre removed is 'le'.
'fab'+'le'='FABLE'
(Other definitions for fable that I've seen before include "Short moral story" , "Old wives' tale" , "there may be a moral to it" , "Moral tale" , "Aesop story" .)