But it is also a weakness because it can make your horror story predictable. The trick is to know and hit the horror story beats, but twist each one to throw off the audience's expectations.

There are 15 special story beats of the horror form. One is the Barrier.

The Barrier is the initial wall stopping the opponent from getting in. It's what keeps out the other side that will inevitably bring destruction to the hero and his or her society. We see this step in many horror stories, including King Kong, Pet Cemetery, and the story of Pandora's Box.

Key point: the barrier is real and external; it's a locked gate to keep out the opponent. But it must also be internal. It is the rational division in the mind blocking the negative part in the self that the hero either cannot or should not access.

Deeper meaning: this Barrier is the thing preventing the slippery slope. Once the boundary is crossed, the hero cannot stop and the ramifications, and the horror, grow worse at a rapidly increasing pace.