Well, it could be about various terrifying events that happened in the woods. Maybe it involves strange noises, encounters with wild and dangerous animals, or even something more supernatural like ghostly apparitions. Since it's based on a true story, it might be a recount of someone's harrowing experience in the forest.
It might be about a group of people who went into the woods and faced something truly terrifying. It could be that they got lost and then started to experience things that made them fear for their lives. For example, they could have stumbled upon an old, abandoned building in the woods where something bad had happened in the past, and they began to sense an eerie presence. It might also be related to the natural dangers in the woods like getting trapped in a sudden storm or facing a territorial wild animal.