The term 'story opener' refers to the beginning of a story, which is typically used to introduce the characters and setting. The crossword solutions for this term are ONCE (4 letters), PARTI (5 letters), and PAGEONE (7 letters). ONCE is an adverb that means 'at one time' or 'on one occasion'. PARTI is a noun that means 'a political party or faction'. PAGEONE is a noun that refers to the first page of a book or newspaper.