Xi Dai, a theoretical physicist at the Institute of Physics of the Chinese Academy of Sciences, started his physics career right after the discovery of the first high-temperature superconductor. Infected with “high-Tc fever,” he enrolled in materials sciences and condensed matter physics programs, hoping to contribute to developing a theory for this phenomenon that could guide the search for a room-temperature superconductor. While the high-Tc puzzle is still unsolved, Dai’s theoretical work in related topics put him right at the center of a new condensed matter craze—the physics of topological materials. In 2015, he was part of one of the teams that discovered Weyl semimetals, exotic topological solids in which electronic excitations behave as massless particles known as Weyl fermions. Xi Dai explained to Physics why these materials have him hooked and why condensed matter physics offers untold “hidden treasures” for young researchers to explore.