Well this is just my idea, but you could do something like this:
Somebody is in a forest camping with their family, and they hear noises from outside their campsite. They all split up and try to figure out what is was. The youngest boy in the family (13), find a trails of giant footprints, and follows them. As he does, the noises get louder and louder until-
blah blah blah, the rest is up to you.
