Last summer, coral reefs in Hawaii turned white when high ocean temperatures caused corals to lose the microbes that normally give them color. These microbes also provide nutrition and disease-protection to corals, and without them, "bleached" corals often die. However, corals can survive—and even adapt—if their healthy microbes come back. Now, we are tracking coral recovery in Hawaii up close to understand how the fate of these corals, and even the future of coral reefs, may depend on microbes.