With the world falling apart around them, Thomas and his friends find themselves starting to run out of food. They're not the only ones, however, and they soon discover that some people have gone to disturbing lengths to keep going. Some people will do anything to survive, and dark secrets are lingering in the heart of Philadelphia.

Meanwhile, Elizabeth has found a place to hide from the world, but her sense of security is shattered by some new arrivals. Do the Longford family simply want to rest for a few days, or are they hiding a far more sinister agenda?

Days 349 to 356 is the eleventh book in the Mass Extinction Event series. The book ends with a cliffhanger, and readers are advised to start with the first part of the series.