Note altered reality in this story (5,4)
I believe the answer is:
fairy tale
'this story' is the definition.
(thesaurus)
'note altered reality' is the wordplay.
'note' becomes 'fa' (musical note).
'altered' indicates anagramming the letters.
'reality' with letters rearranged gives 'irytale'.
'fa'+'irytale'='FAIRY TALE'
'in' is the link.
(Other definitions for fairy tale that I've seen before include "'Once upon a time...'" , "A magical story for children" , "''... of New York'' (The Pogues)" , "Children's story with magical beings" , "Children's magic tale or incredible story for adult" .)