So far the volunteers have successfully been losing lost weight, but now the honeymoon period is over. It is the final two months of the diet, and their minds and bodies are fighting back. Dr Chris van Tulleken and Professor Tanya Byron find out if the new personalised diets will help them stay on course, and the experts reveal the scientific secrets to permanent dieting success.

This episode discusses the human exploration of Antarctica, in particular the mission led by Captain Robert Falcon Scott, whose team died on the way back from the South Pole. It shows the scientific work in the modern human bases in Antarctica, especially Mawson Base and its observation of Adelie Penguins (partially through tracking devices). The second half of the episode describes how the series was made. Most crucial was of course the camera work. To get access to the wildlife of the sea, for example, boats, divers, suspended capsules and remotely controlled cameras mounted on inflatables were used. Particularly dangerous to divers were Leopard Seals and other predators. The film concludes that although working in Antarctica is now much easier than during the early days of exploration, human footsteps on the continent are still exceedingly rare in part because of international treaties prohibiting industrial exploitation.

Cicero is finally undone by his duplicity in the form of Titus Pullo, acting upon Octavian's request to assassinate all supporters of Brutus in Rome. Pullo and Vorenus enjoy a happy if counterfeit outing with their families in the countryside to hide their assassin mission.
Vorena the Elder's dangerous dalliance with one of Mimeo's men continues, and the torrid affair between Octavia and Agrippa escalates. Atia's casual cruelty to ask for the assassination of people she doesn't like results in complete disaster for Octavia's friend Jocasta.

Sodom and Gomorrah, a tale of two cities incinerated by a hail of fire and brimstone. Is this a fantastic fable, or could it be a near apocalyptic disaster from space? In this episode, we will check into the mysteries relating to the destruction of both cities. Were they astronomical events?
Newly discovered evidence might hold the secrets to one of the Bible's greatest mysteries.

Quinto sets out to discover whether aliens exist and what evidence we have to prove it. He meets with several who say they have encountered extra-terrestrial life–a man who has been abducted by aliens several times since childhood; a man who claims to have extracted an alien implant; and a woman who shows Zachary what it feels like to be abducted into a spacecraft.
Zachary also meets with the world's leading scientists at SETI in Green Banks, West Virginia. There, utilizing the world's largest telescope, they show him the methods they employ to communicate with potential other-worldly visitors and what this research has taught them about a mysterious radio signal they picked up 3 billion light years away.

Over the last years, the world has experienced an energy revolution, driven by an urgent need to green the grid and save life on Earth as we know it. 50 years ago, a devastating oil crisis kicked off an energy revolution. The world set course to cut the costly habit of burning fossil fuels. With the urgent new threat of a changing climate, the drive to unleash the power of the sun, earth and wind has accelerated into a race for humanity's survival. Change is taken place but, is it happening fast enough to secure our future? Technologies are right here, right now, and they will enable the transition to 100% renewables, because winning the energy race means a win for the entire world.