Summer has been full of secrets and adventures for Susan in Chicago, so far. In her neighborhood, she has tried to adopt most everyone who does not have an extended family around them, and this leads to a dog-walking business with best friend Terry. They meet new people and are drawn in to others' cultures and joys and sorrows and are getting paid!
Not all is going great for everyone. Some neighbors are drifting away or caught up in crime. Then, one day Susan a surprise realization--a friend is missing under mysterious circumstances. Susan finally figures out several puzzles, and feels helpless when she discovers a crime, but is determined to get justice. But how? She struggles with being a supportive friend but also wanting to exact revenge. In the midst of the crisis, friends go to back to school, Autumn is coming, and a neighbor veteran looks out for kids and shows Susan a way.
A mystery is revealed, then resolved in a spook-tacular fashion, where Susan becomes a monster force to protect the living. Susan becomes an avenger of wrongs leading up to the long-awaited Halloween party at friend Sharon's. Friends and neighbors rally around their community. New friends step up and old friends may have to leave, but Susan keeps forging on trying to build community around her.