Jack and the rest of the Guardians knew their purpose in the world. To protect the children. But when an old threat returns and threatens to up-end everything that they work to protect, they have to join forces with an not entirely willing spirit. Samantha Gale, Sam for short, was used to being ignored. Children didn't believe in her so she wasn't seen and the other spirits tended to give her as wide a berth as possible. So she accepts it, and does the best job she can with the abilities she has. But when she is blown, literally, into the world that has tried so hard to avoid her and suddenly is a Guardian, she must face a threat greater than anything she has ever seen before. She has to trust in herself, and in her powers.