Kate Humble and Simon King report from Zambia, following the lives of the animals living along the Luangwa River at a critical time in the seasons. It hasn't rained for seven months but the clouds are building and the drought could break any day. The river is the only water around, and predator and prey are squashed uncomfortably close. Lions and wild dogs, the latter one of the most endangered species on Earth, compete for territory as elephants try to keep cool in the fierce heat and leopards enjoy days of plenty. 75 cameras capture every moment as it happens through the last days of the longest dry season in memory to the arrival of the rains that will change everything.