Through a skylight in the cave, the characters see the sun and moon flashing across the sky like a strobe light—each flicker representing a full day passing in the blink of an eye.

The story kicks off with an archaeology professor, Hopper (Andrew Wilson), who goes missing while exploring a remote Texas cave system in search of the legendary "Fountain of Youth". When he fails to return, a group of his students—and a couple of tagging-along younger kids—set out to find him.

What makes Time Trap so gripping is its central conceit: . Inside the cave, time moves at a crawl compared to the outside world.