Garrett McNamara and his team return to Nazaré for another season of surfing. The team struggles through a number of accidents and challenges but eventually develop a set of safety procedures that enable them to surf Nazare's wave with less chance of injury or death. The struggles pay off when McNamara catches a nearly 80 foot tall wave that catapults him to international fame and makes him the holder of the world record for largest wave surfed.

After losing his drive to continue surfing at Nazaré, Garrett McNamara decides to return to competitive surfing at other big-wave sites. In order to compete in a tournament at California's Mavericks surf site, he must surf there regularly, something that he has done many times in the past. McNamara returns to Mavericks only to suffer a horrific injury on a wave he should have aced.

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.

To survive Mars, our species will need to evolve how we eat, drink, and build our homes. Will we need our genes to evolve as well? Sometime in the future humans will leave Earth to colonize Mars, and in doing so will begin to adapt to life on another planet in surprising ways. Evolutionary biologist Dr. Scott Solomon foresees a series of changes to our species from the size of our hearts and heads to the pigments in our skin.

As dozens of top surfers from across the world arrive in Nazaré to train and prepare for a major big-wave competition, Garret McNamara continues to struggle with his physical injuries and mental preparedness. He knows he is not ready to surf in the competition but seeing the other surfers makes him consider competing anyway. Garrett also has misgivings about the state of safety plans at the competition, and tries to convince the organizers to beef up their plans.

Edgar Davidson agrees to talk to investigators but tells a different story. Cathy’s sister Marilyn indicates her interest in solving the case. Tom Nugent casts doubt on Gerry Koob’s story about the night of Cathy’s disappearance. The search for the other man at Cathy’s apartment Pete McKeon may have information about Koob’s relationship.
What Cathy’s roommate Sister Russell knew about the abuse and Cathy’s relationship comes into question. 'Jane Doe' and 'Jane Roe' meet for the first time and talk about the Keough. Abbie investigates Baltimore’s investigation into the abuse reports they received. Marilyn Cesnik Radakovic recalls receiving a mysterious letter from her sister after her death.