Twelve-year-old Crow has a good life on a small island off the coast of Massachusetts. Under the care of her guardian, Osh, and their neighbor Miss Maggie, who lives on the nearby island of Cuttyhunk, she wants for little. She’s happy helping Osh with the fishing and cooking, and Miss Maggie with the care of her animals. But there’s an unexplained mystery in her life that keeps looming larger as she grows older.

No one knows where Crow came from, only that she arrived as a baby, alone in a small boat. The mere possibility that she might have come from a leper colony on the nearby island of Penikese is enough to make most of their neighbors, except for Miss Maggie, afraid of Crow. Even though she’s never shown any signs of leprosy, she’s not welcome in school, at the library, or anywhere else where there are a lot of people nervous about possible infection. People back away from her, refuse to take her hand, and sanitize doorknobs after she touches them.

Crow wants more and more every day to know where she really came from, and she wants to know who her family was. But investigating these mysteries may bring more turmoil upon herself and her loved ones than they can handle.

“Beyond the Bright Sea,” Lauren Wolk’s follow-up to her acclaimed middle-school novel “Wolf Hollow,” is another strong story with a brave and capable young heroine. Wolk’s descriptions of life by the sea, with all its hard work and all its loveliness, are beautifully written. Most of her characters, too, are complex and well-drawn.

Osh, though he never adopted Crow officially, is a great example of a loving adoptive parent. He took in the mysterious baby in the boat when most people on the islands wanted nothing to do with her, and has loved her, taught her, and treated her like his own daughter all his life. His love stands in stark contrast to the fear of others.

But it’s hard on Osh when Crow begins to show an interest in finding her family of origin — partly for the reasons that it’s usually hard on adoptive parents, and partly because he knows more of the world than Crow does. He himself has a mysterious background, having left his own family and friends behind and fled from a war-torn country, and he’s afraid of what could happen to Crow when she ventures beyond their little chain of islands.

To some extent, he’s right to be afraid. Crow’s search attracts the attention of a violent criminal who knows that there was more on Penikese than just a leper colony, and is determined to find the island’s hidden treasure. His attacks on Crow and others constitute probably the biggest content issue of the book, but they’re not described graphically or explicitly. There’s no profanity and no sexual content; there are occasional, generally positive mentions of religion.

Though Crow doesn’t find all she sets out to find, she does make some important and satisfying discoveries, and not just about her family. Though she’s been so hurt by the islanders’ actions, she starts to learn to understand and forgive them. She learns about greed and what it can do to people, and about sacrificial love and the great difference it can make in even the most miserable life. She learns a few things about obeying her adoptive father when he tells her to do or not to do something, for her own good. And she learns to value what she has more than ever, even while reaching out for the things she wants. This realistic and interesting character and her emotional and moral growth make “Beyond the Bright Sea” a good read for its middle-school audience.

Image copyright Dutton Books for Young Readers. Review copy obtained from the reviewer’s local library.

Gina Dalfonzo is editor of BreakPoint.org and Dickensblog, and the author of “One by One: Welcoming the Singles in Your Church” (Baker, June 2017).