Natural ability in story-book (6)
I believe the answer is:
talent
'natural ability' is the definition.
(talent is a kind of natural ability)
'story-book' is the wordplay.
'story' becomes 'tale' ('tale' can be a synonym of 'story').
'book' becomes 'nt' (I've seen this in other clues).
'tale'+'nt'='TALENT'
'in' is the link.
(Other definitions for talent that I've seen before include "Sort of scout - old money - gift" , "Innate aptitude" , "Flair, aptitude" , "Natural ability or gift" , "Inborn ability or facility" .)