Since 2010, IceCube, a detector frozen in the ice beneath the South Pole, has snared neutrinos from deep space. The universe is awash with these fleeting, almost massless particles, but IceCube is after a rare subset. They are messengers from distant cosmic accelerators such as supernovae, neutron stars, and black holes. IceCube has caught about 300 in its cubic kilometer of ice, but has had less success tracing them to their probable source—just two so far. Now, it is poised to get help from new detectors that trade Antarctic ice for deep northern waters.