Credit: Ely Brown/ABC News

ABC News' Ely Brown reports:

It's 11 p.m. Sunday night and under a star-filled sky four Zodiac boats slip silently through the calm dark waters of the inland channels along the Virginia coast. The mission for the men on board: Make their way to a location about a mile down river, hump it down a mile of railroad tracks and at pre-planned intersection rescue two hostages taken by enemy forces.

It's Hell Night at the Extreme SEAL Experience. Run by former Navy SEAL Don Shipley, Extreme SEAL allows civilians to test their metal in the cauldron of the military's toughest training regime. Located in Chesapeake, Va., the week-long "Advanced Training Courses" start at $1,890, according to the program's website.

" Nightline" embedded for a week of night ops, close-quarters combat training, and endless, endless pushups, sit ups, jumping jacks and whatever other sadistic calisthenics the ex-SEAL instructors can come up with.

PHOTOS: Enduring the Extreme SEAL Experience

With a name like Hell Night, it's easy to think that the purpose is to force the men to their breaking point. But instead, it's all about getting the participants to work as a team. With a class made up of people ranging from 15-year-old high school students and young aspiring SEAL candidates currently going through the real enlistment process to middle-aged ministers and physicists looking for a physical and mental challenge, Hell Night forces them to work together - and for each other - in order to survive.

With five more days to go, who will make it to the end? Already a popped hamstring has sidelined one returning Extreme SEAL vet. But the men have already learned to work together as well, helping each other out by inspiring them to do that one last push up, lift that log up higher, and paddle that boat a little harder. A big mission planned for the end of the week will rely on the teamwork that was first forged in the cauldron of Hell Night.

Tune into " Nightline" TONIGHT at 11:35 p.m. ET/PT to find out what happens.