When a potentially devastating new virus emerges in early 2020, acclaimed documentary filmmaker Rehad Desai is already following a vaccine clinical trial that could finally end the decades-long HIV pandemic. Widening his lens to trace this "tale of two pandemics," Rehad confronts the harsh reality that, while antiviral drugs are vital, eliminating the accelerating threat to humanity from emerging diseases requires making those drugs available to all, while also tackling the poverty, malnutrition and lack of access to healthcare that are fuelling the rise of dangerous new pathogens - and the clock is ticking.