1 Dark creatures steal children
The Dark creatures that live in the tunnel steal young children. The dark creatures come after children and attack their parents.
2 Chief Collins was aware of the story
Chief Collins knew what was happening in the village yet he accused Dean Booth of being crazy to cover the story up. Chief Collins didn't want people to know about the nature of the village.
3 Chief Collins kidnapped two children
Chief Collins kidnapped two children and delivered them to the tall Dark man, a dark creature, in exchange of his daughter who was kidnapped by him. Chief Collins did so to save his daughter Nikki.
4 Nikki remembered the exchange
As Nikki checked the files on her father's computer, she remembered the exchange that happened between her father and the tall dark man. She then realized that her father knew all about it.
5 Chief Collins was allowing this to happen
Chief Collins was allowing the creatures to steal children in order to keep his daughter safe. This is why he was covering up the story.
6 Dr John sacrificed himself for his child
Dr John entered into the cave in order to allow his child Nathan to escape. Nathan managed to escape by Dr John who was trapped inside the cave.
7 Dr John turned into a dark creature
When Dr John woke up and went back home, he realized that his family could't see him. Dr John turned into one of those dark shadows that can only appear as shadows in the corner of one's vision.