Richard Vevers left a career in advertising to document what he calls the ocean's silent crisis: coral reefs dying off at a pace almost no one outside marine science has registered. He assembles a team of divers, photographers, and scientists to rig underwater cameras that will capture time-lapse footage of bleaching events as they happen, a technical challenge that eats up equipment and patience before it works. The crew tracks a mass bleaching across the Great Barrier Reef and other reef systems, watching coral that has thrived for centuries turn white and die within weeks as ocean temperatures climb. Interviews with coral scientists lay out why reefs matter beyond their color, as nurseries for roughly a quarter of marine species and buffers for coastlines. The time-lapse sequences are the film's real argument, showing in compressed days what would otherwise take a diver years of visits to notice, and they turn an abstract statistic about warming water into a visible, moving loss.