Rookie caver, Kevin, leads an expedition into the depths of a Tennessee cave. Three hopeful rookies compete for a high-flying position with the Sonoma Marin Tree Men. A novice flyer travels to Africa to be take a rigorous bush pilot course.

A rookie tree climber jeopardizes his team when he ignores expert advice about scaling a redwood; Dan and Erik attempt a dangerous underwater welding job in San Diego; Amateur pilot, Ron, gets his first taste of canyon flying.

Hoping for a job as a commercial diver, Erik welds a patch on a sunken submarine; Rookie heavy haul driver, Fred, battles through Hurricane Patricia; three lessons into his bush pilot training, Ron ends up in a hospital.

A rookie diver struggles underwater to rig a sunken yacht; a heavy haul trucker tries to transport a crane through a hurricane; a tree man fells a large, dead Eucalyptus tree.

Rookie tree man Tomas freezes in fear halfway up a redwood. Greenhorn diver Erik descends deep into the ocean to collect research samples. And rookie volcanologist Sarah attempts to scale an active volcano in order to land her dream job

Sarah continues her research on the volcano; Nate and Tomas work through a challenge together; Mike climbs a giant wind turbine.