Four teenage urban explorers must walk six miles through the dangerous ruins of Detroit to reach a pay phone after getting robbed in the city?s abandoned underbelly.

I think this is a pretty good idea. However, I think it needs one main character to be the focus and she/he should have a flaw to overcome. Maybe he or she could be leading his/her friends out of the city and he/she has never had to be a leader before. Also, the inciting incident – getting robbed in the city’s abandoned underbelly – should go first and there should be greater stakes in the overall logline. This is just an example but something alone the lines like this:

Getting robbed in the city’s abandoned underbelly, a timid high school student must lead his three friends through the dangerous ruins of Detroit before they are discovered by rivaling gangs.