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.

强大的密西西比河正受到多方面的威胁——从外来入侵者驱逐标志性的本地鱼类，到大片绿色藻类扼杀河流生命。杰里米·韦德 (Jeremy Wade) 会见了科学家、渔民和致力于拯救这条河流的领导者。