A synopsis to think over (6)
I believe the answer is:
digest
This clue is a double definition.
'a synopsis' is the first definition.
(thesaurus)
'think over' is the second definition.
(I've seen this before)
'to' acts as a link.
(Other definitions for digest that I've seen before include "Gradually come to understand" , "Periodical that summarises the news" , "Periodical summarizing the news" , "Break down in the stomach" , "book" .)