Article on yours truly contains a unifying idea (5)
I believe the answer is:
theme
'a unifying idea' is the definition.
(I've seen this in another clue)
'article on yours truly' is the wordplay.
'article' becomes 'the' (the definite article in English).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'yours truly' becomes 'me' (the person who set this crossword).
'the'+'me'='THEME'
'contains' is the link.
(Other definitions for theme that I've seen before include "Topic, leitmotif" , "[(type of) PARK]" , "Topical item" , "Subject (on which person writes, speaks)" , "Main idea or topic" .)