"For many years Miss Maggie McCullen has been the keeper for the Port Carrick lighthouse. The people of Port Carrick are proud of her. 'She keeps that big light going,' they say. 'Never misses a night. You can't count the lives Miss Maggie and her light have saved.' And while the people are grateful to Miss Maggie, they also worry about her and her lonely life at the lighthouse.
But they don't know she has her cat, Sailor Boy, for company. Because Sailor Boy is no ordinary cat. He's a ghost cat. He can make himself visible or invisible, especially when visitors come to call and he wants to be mischievous. But when a fierce storm comes and Miss Maggie needs special assistance, Sailor Boy proves how extraordinary he really is."