The Atlantic is the second largest ocean on the planet. It is the resting place of the Titanic, home to the mysterious Bermuda Triangle and is the youngest of the Earth's great oceans. It reaches depths of 8,500 metres. Oceans investigates this influential body of water from a group of islands in its western reaches - the Bahamas.

1917. People have had enough of the war. Behind the scenes, uprisings are brewing, like the one that toppled the Tsar in Russia; on the front soldiers begin to mutiny as they did at Chemin des Dames in France. German submarine attacks in the Atlantic will finally pull the Americans into the war, but they arrive too late to help prevent the carnage of the Battle of Passchendaele.

Zachary Quinto sets out to research the strangest creatures dug up from the depths of the ocean and to see how much they lend to the monsters that are depicted in myth and legend. Starting in Australia, he meets with a teenager who was savagely attacked by a swarm of mysterious flesh-eating monsters, only to jump into the water himself the next day amongst highly venomous sea creatures.
From the carnivorous fish of American rivers to the eyeless monsters of the Atlantic Ocean, Zachary finds some merit in these old monster stories and is starting to understand just what we mean when we say that we know less than 1% of what waits in the depths below.

The story of Tilikum, a captive killer whale that has taken the lives of several people , including a top killer whale trainer, underscores the consequences of keeping these powerful animals in captivity, the problems within the sea-park industry, the man's relationship to nature, and how little has been learned about these highly intelligent and sentient mammals.
Tilikum was captured in the northern Atlantic Ocean in 1983 and taken to Sealand of the Pacific, a now-shuttered park near Victoria, British Columbia. Former Sealand trainers interviewed in 'Blackfish' say the park’s female killer whales would aggressively gang up on Tilikum, particularly when they were confined in a 20-foot-by- 30-foot pool overnight.

There is a region of space that is dangerous for reasons we don't yet understand completely. We see an increased flux of energetic particles in this area and higher-than-usual levels of radiation. It's called the South Atlantic Anomaly. Some scientists now think the long-term effects of this danger zone may be far wider reaching than anyone ever expected, and it may even have implications for the future of humanity in space and on Earth.

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.