cover story vs semblance

cover story

noun
  • A fictitious account that is intended to hide one's real motive. 

  • A story included in a publication that is highlighted on the front cover. 

semblance

noun
  • likeness, similarity; the quality of being similar. 

  • the way something looks; appearance; form 

How often have the words cover story and semblance occurred in a corpus of books? (source: Google Ngram Viewer )