The series returns with a visually stunning dispatch from the far corners of the world, as CNN's Chief Climate Correspondent Bill Weir follows the humpback whale migratory journey from Antarctica all the way to the coast of Colombia. 

Humpback whales have the longest migration route of any mammal on earth, and in this immersive episode, Weir embeds with a team of researchers as they venture from Antarctic ice to rich South American jungles, hoping to discover the impact of climate change on these magnificent creatures. While humpback whales have made a spectacular comeback in the last fifty years and are considered a beacon of modern conservation, they are now having to face some of the biggest existential threats of all. On this journey, Weir confronts one of the last of the whale hunters in Iceland and while climate change deniers blame offshore wind development for a spate of dead animals washing ashore, he digs for the truth with some of the leading experts in the world. Amid the striking landscapes and diverse coastlines, Weir also learns how whales have the ability to absorb and store carbon, making them one of our greatest allies in the battle against climate change.

"I was a little boy when recordings of humpback songs sparked a movement to save the whales and reversed a manmade extinction," said Weir. "Fifty years later, artificial intelligence could help us understand the lyrics of those songs just as science realizes the enormous ocean repair services provided by whales. They are literally the biggest allies we have in the fight against climate change, and by saving them, we help save ourselves."

CNN Political Commentator and former Obama administration official Van Jones delivers an incisive examination of the state of politics in Tennessee. He returns to his home state in the lead-up to the Republican primary election on Super Tuesday. 

In April 2023, Tennessee's Republican-controlled House of Representatives voted to expel two Black lawmakers a week after they joined a gun reform protest in the chamber prompted by a deadly shooting at a Nashville school. This remarkably rare and emotionally charged decision set the scene for Jones' return to his home state and his former place of employment in the state capitol, where he interned for the House Majority Leader in 1989. Jones unpacks how Tennessee's politics have swung sharply to the right since then by examining how gerrymandered redistricting, racial tensions, and "culture war" rhetoric have transformed the state government into a conservative supermajority. The trend set by Tennessee has played out across the southern US.

"In the Tennessee in which I was born and raised, we always had our struggles. But people usually tried to treat each other in a decent and neighborly way." said Jones. "But I returned to find the state legislature that launched my political career transformed beyond recognition — by a ham-fisted, hard-hearted politics of open hostility to minority viewpoints."

Tennessee represents a national tug-of-war over the direction of the country's politics at large. Jones speaks with politicians on both sides of the aisle to get their take on the tribalism between parties and its implications for the future of governing. This episode features interviews with reinstated Democratic State Representatives Justin Jones and Justin J. Pearson, Republican State Representative Gino Bulso, Republican Sumner County Commissioner Matthew Shoaf, Chair of the Tennessee Democratic Party Hendrell Remus, local organizers, and even members of Jones' family.