Thousands of central North Carolina residents spent much of last week in the dark following an attack on two electric substations. It follows years of warnings from the federal government that the power grid was an attractive target for extremists. We examine how this attack upended daily life and look at what can be done to protect the grid going forward. Guest: Whitney Wild, CNN Law Enforcement Correspondent To learn more about how CNN protects listener privacy, visit cnn.com/privacy (https://cnn.com/privacy)