Freud's Dream Theory

Freud believes that dreams are spyholes into our unconscious. Fears, desires and emotions that we are usually unaware of make themselves known through dreams. Dreams as said to be fundamentally about wish-fulfillment, this also includes negative dreams.
Negative Dreams tend to consist of punishment and other forms of anxiety which are a form of wish-fulfilment, the wish being that certain events never occur in reality. On many occasions these dreams interpreted as a warning.

Freud’s work was solely concerned with internal stimuli. These consist of strong negative emotions, forbidden thoughts and unconscious desires being disguised or censored in some form or another. When confronted with these, the dreamer would become distressed and would eventually wake up. 

Freud believed the dream to be composed of two parts. The manifest and the latent content. The manifest content is what a person would be able to consciously describe to someone else when recalling the dream. Freud suggested that the manifest content possessed no meaning whatsoever because it was a disguised representation of the true thought underlying the dream. On the other hand, the latent content holds the true meaning of the dream. In this case it is the forbidden thoughts and the unconscious desires that will never truly be revealed because it is difficult to remember when conscious.