Mary Walker couldn't help herself, she loved living in the Robbins Reef Lighthouse in New York Harbor, although her mother wouldn't unpack any of their bags because she planned on leaving the light as soon as possible. As the days passed, Mama and Papa taught Mary and her brother Jacob how to tend the light and when Papa got sick and Mama had to take him to the hospital in New York City, Mary and Jacob tended the light by themselves. Mary's adventures include a trip to New York City to buy forbidden overalls and a daring rescue of Scotty the dog.