This would be an idea that would be sort of run like a Found Footage film. The characters would be a group of cops or FBI agents or something (cops probably, due to the lapel cameras) In the Days leading up to a global disaster. The characters investigate a string of suspicious kidnappings and murders involving an evil cult. There are 13 days to investigate, and depending on the outcome of the investigation, the characters will either be killed, Some may survive, or all will live happily ever after. Oh, and I may put in like small side investigations, or even a Bank Robbery or something.
This is Advanced, because it will involve at least two paragraphs of text. One explaining what the character who found the camera after the "End" happened (or is reviewing the Camera footage from the investigation.) is doing, and the Main character's POV. Yes, there will also be sections of break from Investigation.