One year after Hurricane Sandy's deadly strike, NOVA follows up on its 2012 film "Inside the Megastorm" with a fresh investigation of the critical questions raised by this historic storm: Was Sandy a freak combination of weather systems? Or are hurricanes increasing in intensity due to a changing climate? What can we do to prepare ourselves for the next Sandy and what progress has been made toward making our urban infrastructure more resilient? Much of Sandy's wrecking power was due to an extreme storm surge that left large swaths of New York and New Jersey underwater. And with sea levels on the rise, flooding will only become more frequent. What is the role of global warming in driving these rising seas and what will it take to make cities like New York more resilient? NOVA travels around the world to see how other low-lying urban areas are combining extraordinary engineering with natural landscape restoration and a smarter, more flexible power grid to prepare for an uncertain future. At the same time, NOVA meets the climate scientists who are racing to understand how a warming world will affect extreme -- but unpredictable -- weather phenomena like hurricanes and tornadoes. To many, Sandy was a wake-up call: one year later, are we still listening? And how will we answer?