The meteoric rise of renewable energy has consequences for our electricity supply. While coal and gas fired power stations can generate electricity whenever you need it, renewables are intermittent by nature. So we need a backup plan for when the wind stops or the sun goes down.
All over the world, engineers and scientists are racing to solve one key problem; how to safely and efficiently store electricity at a huge scale but at a low cost. The quest is producing some truly remarkable ideas and this episode details three of them.

In the second episode, Dreadnoughtus males compete for the right to mate. Lizards are hunted by Velociraptor among a group of sleeping Tarbosaurus. A Mononykus forages for termites and investigates new food options after a brief rainstorm. Several types of dinosaurs congregate around a watering hole in Mongolia.
Above the deserts of North Africa, aerial combat ensues as male Barbaridactylus pterosaurs fight for the attention of females below. A herd of Secernosaurus brave the harsh gypsum dunes in search of nourishment.

In the fourth episode, Dromaeosaurs stalk a hadrosaur herd as they cross a freezing river. Male Ornithomimus raid rival nests to bolster their own. Olorotitan raise their offspring on fertile volcanic fields but contend with biting mosquitoes.
Troodontids hunt mammals flushed out by a forest fire. A juvenile Antarctopelta scours the forest for a new winter den. Within the snow-covered forest, a tense standoff develops between ancient rivals, Pachyrhinosaurus and Nanuqsaurus.

In 2011, a Social Security lawyer named Eric C. Conn and a judge named David Daugherty were investigated for committing massive fraud over many years. Conn figured out that he would get paid a hefty retainer for every Social Security disability payment he managed to get approved, so he and Daugherty (who need quick cash to pay for his daughter’s upcoming narcotics trial – which presumably meant bribing an awful lot of people) came to an arrangement.
In the second episode, Investigators starts to collect evidence against Eric and Judge Daugherty. The whistle-blowers are pressured.

Jennifer Griffith and Sarah Carver were working for the Disability Administration and noticed all this corruption firsthand. They wrote to the Social Security Administration, wrote to lawyers, wrote to the president of the United States. But nothing ever came of their complaints until the Wall Street Journal story broke. Then, with national attention brought to Conn, the Senate, the FBI and the SSA (who’d been enabling the fraud the whole time) finally stepped in.
Series finale. Eric leads the government on a wild goose chase. The fallout from the fraud takes its toll on a struggling Kentucky community.

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'.