It's been about a year since Ben, Caroline, Owen, and Joey beat the agents and saved the bell. Ben is still the walker, Caroline and Owen are on the road now, trying to find the bell, and Joey is still working in the thinning. Caroline and Owen are getting help from other members of the Circle of the Crow, but the bell hasn't been found yet.
All that changes with Grant, when a new Keeper is found. Can the Circle of the Crow save him? It's going to be an interesting battle. Very highly recommended.