The Big Bang must have produced equal amounts of matter and antimatter, but the universe is made of matter and all antimatter annihilated and disappeared. The standard model of particle physics does not explain this imbalance between matter and antimatter. Neutrinos, which are among the most abundant particles in the universe, may hold the answer. New experiments in Japan, Europe, and the United States will try to reveal the neutrinos’ secrets by looking for clues in nuclear reactions, high-intensity neutrino beams, and astrophysical observations. They will examine whether neutrinos are their own antiparticles, look for the violation of the matter-antimatter symmetry in neutrino oscillations, and search for active galactic nuclei that may be the source of ultra-high-energy neutrinos. Their results will help us understand whether neutrinos are the reason we exist.