The bitter cold
When Caroline is journeying toward her own truth, revisiting the house she was abducted from, she suffers freezing weather that literally starts giving her frostbite. This imagery helps the reader to understand the absolute desolation the journey represents to her. By addressing these memories which she has repressed, Caroline must face the truth about her own inherited dysfunction. This means that her outside world and her inside world are the same—bitter, wearisome and cold.
The Forest Park paradise
When people hear that someone was "raised in the wild," they have one kind of association, but Caroline didn't feel like she was missing out. The imagery helps to explain how Caroline feels about her wilderness life. She loves it. She enjoys the fulfilling days with her father, and she loves nature and the beauty of her everyday life. In other words, she lives in a kind of paradise. This paradise imagery helps to explain the nature of her journey, out of paradise and into the 'real' world (like the fall of man).
The suburban park imagery
There is another set of imagery that has unusual connotations in this novel: suburban life. For Caroline, suburbia represents her earliest childhood memories, but now they represent the fact that for Caroline, this life means nothing. Without the grit of her life in nature, she is completely unfulfilled by a regular life. This is shown most clearly when she stares at her sister at the park.
The imagery of surveillance
One weird kind of imagery that the novelist uses is that of paranoia. The paranoiac imagery is simply that the novel explicitly explains what the paranoid delusions 'look like.' They look like a man peeking through his blinds, and he sees images that don't exist. He imagines government employees spying on them. Eventually, Caroline adopts this paranoia herself, but weirdly enough, for Caroline, the dominant use of surveillance imagery comes when she uses her paranoia as an excuse to surveil children in order to find one worth kidnapping. She has gone from being the imaginary victim to being the potential perpetrator of a horrible crime.
