Some reality shows are just harder than others.
Take Darkness, the new offering from Discovery that premieres Wednesday night.
The show puts three participants into separate sections of a labyrinth of caves and challenges them to find each other — and the way out.
Here’s the catch: Contestants can’t see a thing; they are filmed with infrared cameras that emit no light visible to the human eye.
On Wednesday’s episode, the survivalists face snakes, claustrophobia and treacherous paths. One of them even has to cross a frigid underground river. Hypothermia is always a concern since the caves are generally around 55 degrees Farenheit, which gets much colder when you’re wet.
“It’s like we’ve known each other our whole lives,” says Jeff Tucker, a survivalist on the premiere episode. “We became very close out there. You become close with people when you’re literally depending on them for your life.”
Tucker has had an eventful life before appearing on Darkness. He’s a former firefighter and bomb investigator who has had more than his share of extreme adventures. Still, tells PEOPLE that Darkness was one of the most intense experiences of his life.
During one harrowing moment on the premiere episode, one of Tucker’s partners falls down an embankment. (Tucker hasn’t seen the episode yet, but PEOPLE has — and it’s terrifying.)
“It just took me back to some things in my past,” says Tucker, his voice still cracking at the memory. “It was one of the scariest things I’d ever done.”
The special two-night premiere of Darkness airs Wednesday and Thursday at 9 p.m. ET on the Discovery Channel.