Kari & Tory travel across the US, exploring the fun of fear as they enter two of the country's most notorious haunted houses. Along the way, they examine the science behind some of the country's most epic fall traditions.

Kari & Tory ride down a bobsled 60 mph around dangerous curves at Lake Placid, NY, a training ground for Olympian bobsled riders. However, will the thrill of the bobsled match that of the traditional roller coaster ride?

Kari & Tory climb aboard specially outfitted acrobatic aircrafts to test how intense g force conditions affect a person's body and mind.

Tory & Kari head to Sonoma Raceway, and Tory enrolls in professional racing school. He pushes the pedal to the metal, testing the limits of his thrill ride, but things go awry when his car spins out of control.

Kari and Tory make their way to Southern California's Six Flags Magic Mountain to see just how long they can survive on the thrill ride known as Apocalypse.

Tory and Kari are on a scientific quest to find out if there really is such a thing as an adrenaline junkie.

Tory and Kari use accelerometers and state-of-the-art eye-tracking equipment to determine the best place seat on a roller coaster. Their laboratory is Hades 360 in Wisconsin, the only wooden coaster that has a corkscrew.

Tory experiments with Kari senses as she rides Colorado's Glenwood Canyon Flyer ride, which swings riders over a 1,300-foot cliff. She'll be vision and hearing deprived, testing how sight and sounds add to the thrills of a ride.

Kari & Tory conduct a battle of the sexes to determine which gender handles the rush of extreme thrills better. They will test groups of men and women on the launch coaster Thunderbird - going upside-down through 160-ft loop.

Tory & Kari examine how drop rides are designed to exploit riders' natural fear of falling. The two use themselves as test subjects as they plummet 335 feet on Falcon's Fury, the tallest freestanding drop ride in North America.