The episode is a journey through the human gut and the process of turning food into energy to keep the body going. Humans have turned eating into culture, a way to celebrate our roots, to bring us together. But food is really just one thing: Fuel. It's where you get the power to live your life. Even when you're sitting completely still, your body needs a lot of energy to stay on. But nowhere is the need for fuel more apparent than when you push yourself to the absolute limit. And the microbiome, the bacteria living in our gut, plays a great role in all this.

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.

In the second episode, the murder of a political staffer in 2016 spawns a myriad of unfounded conspiracy theories as the man's family and the truth hang in the balance.
Following Seth Rich's murder, his parents filed a lawsuit with Fox News after conspiracy theories about his murder spread across the internet. Mary Rich told NPR that the combined trauma of her son's death and the attacks by conspiracy theorists caused intense and lasting distrust. After the case was resolved, Rich's parents said in a statement at the time that they were 'pleased with the resolution of this matter and sincerely hope that the media will take genuine precautions in the future'.

Nathan decides to practice his own assertiveness in relationships by challenging Angela over their son's religious upbringing. Angela, a fervent Christian, refuses to allow Adam to be raised in Nathan's Jewish faith, so Nathan secretly brings his son to lessons with a tutor in Judaism under the pretense of swimming lessons. Seeking solace outside the house, Nathan opens his replica Alligator Lounge to the public under the name Nate's Lizard Lounge. The co-parents argue over a comedy skit featuring six-year-old Adam as 'Dr. Fart' and a joke about eating faeces, which Angela claims is a Satanic practice.
Nathan rehearses the confrontations with a fake Angela, and in one scenario, she harshly criticizes Nathan's emotional detachment and questions the ethics of the entire production. However, in their real final confrontation, Angela simply decides to quit the rehearsal. Nathan continues to raise Adam, now as a single parent.

Nathan stages a ninth birthday party for Adam, but faces a problem when Remy, one of the child actors who played Adam at age six, becomes attached to Nathan, calling him 'daddy' even after his scenes are over. Remy's mother explains that her son might have trouble understanding the difference between acting and reality. To discover what went wrong, Nathan repeats Remy's scenes with different actors including Liam (a nine-year-old Adam actor), an adult actor, and a mannequin. He then explores what might have happened if Angela had stayed with him and meets with the real Angela, who urges him to forgive himself, as her religious beliefs state.
In an attempt to truly understand the connection between parent and child, Nathan stages a new scenario in which he is Remy's mother Amber and Liam portrays Remy. They re-create the experience of appearing on The Rehearsal and becoming attached to 'pretend daddy' Nathan. After coming to the emotional realization that they should not have done the show, Nathan as Amber seemingly breaks character and tells the fake Remy, 'I'm your daddy.'

Recent archaeological sites in England offer a whole new perspective on the life and death of the seafarers and marines who built the British Empire in the 18th and 19th centuries. The bones of sailors reveal surprising and shocking facts. Apparently not only seasoned men but also half children did their service in the Royal Navy; according to the investigations, the youngest were no older than 13 years. A forensic archaeologist studies the injuries on bones discovered at the site of an battle and suggests how these people may have died.
Three-hundred-and-fifty skeletons, exhumed from Royal Navy graveyards from the age of Nelson's Navy, are throwing an extraordinary new light on how these sailors lived, fought, outwitted their enemy, and, from the oldest to youngest, suffered for victory. These men were the beating heart of the most victorious fleet in history and never have so many of these sailors' remains been available for forensic investigation.
Six remarkable stories stand out: the child sailor, the top man, the American gunner, the freed slave, the marine and the victim of the sailor's most dreaded disease: syphilis. Broken bones, amputations, injuries from blows with a saber or cutlass, sexually transmitted diseases, but also malnutrition - the list of causes of death is long. There is definitely no tale of seafaring romance. These fighters and sailors sailed the globe as cannon fodder, conquered an empire for the crown, and were themselves forgotten. No longer just bones in a box, the men of Nelson's Navy are back from the dead.