Original air date: 04/15/2018 Runtime: 41:50 min. China's Yangtze River is threatened by overfishing, industrial pollution and the loss of iconic monster fish. Jeremy Wade journeys upstream to find out if there are any fish left, and meets the heroes fighting for the future of the river.
Original air date: 04/22/2018 Runtime: 41:49 min. The Mighty Mississippi is threatened on several fronts - from alien invaders pushing out iconic native fish, to vast blooms of green algae strangling life from the river. Jeremy Wade meets scientists, fishermen and leaders fighting to save the river.
Original air date: 04/29/2018 Runtime: 41:49 min. The Danube's scenic route through ten European countries has made it a tourist magnet. But poachers, invasive species and engineering projects have made it one of the most endangered rivers on Earth. Jeremy Wade investigates what can be done to save it.
Original air date: 05/06/2018 Runtime: 41:41 min. The Amazon, the mightiest of all the rivers, comes under immense pressure; Jeremy Wade traces the epic migration of the dorado catfish and discovers the issues putting this great river at risk from leaking pipelines to impassable dams.