Feedback for my story idea? [Sci fi/Fantasy]

The main character is a freshman in Highschool who has joined the cross-country team and while he and his team are doing their after school run, they accidentally fall into a sinkhole and end up in this worlds version of purgatory, the world in between heaven and hell.

The main plot would be about the main character having to lead the team through purgatory and learning how to fight off their foes since he is the only one who isn’t totally miserable here. Throughout the story, he has to connect with his teammates and learn about their backstories, goals, and interests and be able to fit in with the older kids he has looked up to for the past few months he’s known them.

The main party’s they’ll be fighting will be a fantasy inspired demons and sci fi robot angels, hell is a more fantasy inspired area while heaven in more like a dystopian world.

I wanna know any ideas I should add or take out of this premise I came up with.