The term 'IT SOMETIMES THICKENS' can be summarized by the crossword solution PLOT, which is a four-letter word. A PLOT is a sequence of events that make up a story, usually involving a conflict and resolution. It is the backbone of any narrative, and it is what drives the story forward. The phrase 'it sometimes thickens' is often used to describe a situation in which the PLOT of a story becomes more complex and suspenseful.