Stranger story included in article (5)
I believe the answer is:
alien
'stranger' is the definition.
('alien' can be a synonym of 'stranger')
'story included in article' is the wordplay.
'story' becomes 'lie' (I've seen this before).
'included in' is an insertion indicator.
'article' becomes 'an' (indefinite article).
'lie' placed within 'an' is 'ALIEN'.
(Other definitions for alien that I've seen before include "Foreign - film directed by Ridley Scott" , "Stranger" , "Someone from outer space?" , "Martian, say" , "exciting film based in space" .)