The Namib Desert is one of the oldest deserts and also one of the most diverse. With 50ºC (120ºF) temperatures and half a millimetre of rainfall annually, we see how this is possible. Half the size of Oklahoma, from its Skeleton Coast through the sea of sand to the haze of distant mountains this apparently forbidding desert hides secret water sources.

A mammoth Tsunami strikes the eastern seaboard. It would be a disaster of epic proportions. Some scientists believe this catastrophe could happen one day, but how? This episode shows the Atlantic island of La Palma has collapsed several times in mega-landslides. Another could trigger a tsunami with enough power to cross the Atlantic Ocean and decimate the US East Coast.

Within the earth, right beneath our feet, are strange and sometimes deadly secrets. Earthquakes, tsunamis, and volcanic eruptions are just some of the phenomena that are driven by hidden forces deep inside our planet. With the latest sensors and surface scans, a virtual X-Ray of the earth can be generated for study.
In the first episode, we will explore how a vast fault 80 miles off the Pacific Northwest coast. With pressure building for over 300 years, a slip would result in a megaquake and tsunami that will devastate the region threatening 15 million people.

Serial killer Dennis Nilsen narrates his life and horrific crimes via a series of chilling audiotapes recorded from his jail cell. Set against the backdrop of 1980s Britain, when mass unemployment drew young men to London in search of their fortunes, only to find themselves destitute and easy prey, and weaving together interviews from police, journalists, survivors, bereaved families, and - for the first time the killer's own voice, this feature length documentary explores how Nilsen was able to get away with multiple murders and attacks, unchallenged, for five years.

The day of the Nazaré competition has arrived, and Garrett McNamara decides not to compete but instead support his long-time friend and teammate Andrew 'Cotty' Cotton. The competition does not go smoothly, with a major accident that has secondary effects on Cotty. After the competition, Garrett tries surfing at Nazaré again and realizes that can resume big-wave surfing. The episode concludes with retrospectives from a number of the surfers who appeared on various episodes throughout the season.

Garrett McNamara recovers from the injuries he sustained at Mavericks and begins training to return to Nazaré for another season. While surfing at Indonesia's G-Land site, Garrett suffers more injuries that threaten to take him off the waves permanently. Meanwhile, a friend of Garretts catches an 80-foot wave at Nazaré, taking the world record from McNamara. McNamara resolves to continue his hunt for a 100-foot wave.