When the three younger Penderwick sisters go to Maine with Aunt Claire and are separated from oldest sister Rosalind for the first time in their lives, an uncertain Skye is left in charge as the OAP--oldest available Penderwick.

During World War II, Felicity Bathburn is living in Bottlebay, Maine, with her eccentric relatives and their foster child Derek, whom she has grown to love, but when a man claiming to be Derek's true father arrives and starts asking all sorts of strange questions Felicity becomes suspicious of his motives.

Angus and Sadie, two siblings that are of mostly border collie heritage, are adopted by a young couple and start living on a Maine farm, where they begin to learn sheep herding and come to appreciate how they are different from each another.

In 1930 Abby Nichols is an eight-year-old girl growing up in Maine, but as the Depression deepens, and her mother dies, the responsibility of taking care of her family falls to her, and she has to put her dreams of going to college and becoming a writer on hold.