The mood of the book is overwhelmingly suspenseful and bleak. The narrator frequently uses imagery drawn from her surroundings to help the reader feel as nervous and hopeless as she does. For example, in Chapter 10, she remarks on the spooky surroundings while she and Max walk back to Manderley fighting:
The trees were dark here and close together, there were no azaleas brushing the path. The rain dripped heavily from the thick branches. It splashed on my collar and trickled down my neck. I shivered; it was unpleasant, like a cold finger.
The thick, dark trees make it hard for the narrator to see in front of her. The way they obscure her way forward parallels the way her marriage with Maxim appears to be a dead end. She thought her life would begin anew when she arrived at Manderley. Instead, she is stifled by the rules and by the traces Rebecca has left behind. Maxim is showing himself to be a temperamental and neglectful husband. The future the narrator wanted does not look like it is going to happen.
Something awaits her in the darkness, though. She shivers against the drip of rain from the branches and almost feels as though a "cold finger" has snuck up on her and brushed her neck from behind. This image may easily make the reader shiver as well as the narrator. The creepy sensation brings the reader into the suspenseful feeling that worse is yet to come at Manderley. The narrator had better watch her back.