There are a lot of things I’ve learned from interns, one is that agents (and editors) have a language of their own.
In discussing a book, agents will sometimes say something along the lines of, “I had no idea where the story was going.” To authors (and interns) the obvious answer is to tell the agent read the synopsis to figure it out. But readers don’t work that way. Readers don’t get a synopsis and readers don’t refer to a synopsis. If after three chapters a reader has no idea where the book is going (is it a romance, a mystery, a SFF) she’s going to stop reading. Agents are readers first.
There needs to be a sense from the beginning of your book about what kind of journey you’re taking the reader on and where it will lead. Very few people are willing to get on a 10-hour plane ride without an idea of whether they should have packed a swimsuit or parka, a French language guide or a guide to the Outback. A passport or drivers license. You see where I’m going with this.
Each genre has a certain voice, it’s the tone you feel, the atmosphere of the book. Each page, each paragraph, needs to lead to the next and lead the reader on a journey she at least understands. She should know if she’s on an action adventure, going to fall in love, or solve a crime. Of course there are going to be unpredictable twists and turns, but that’s, I guess, predicted.
If you expect that the reader should get her information from a synopsis you’ve failed. If a reader says she didn’t know where the story was going you need to go back and fix your book.