Selena Lucy Landry (named for a ship, as every sailor's child should be) has been frightened of the water ever since she lost her father at sea. But with no one else to care for her, she is sent to foster with the Martins, a large Anishinaabe family living on a lighthouse in the middle of stormy Lake Superior.

The Martin family is big, hard-working, and close, and Lucy--who has always been a dreamer--struggles to fit in. Can she go one day without ruining the laundry or forgetting the sweeping? Will she ever be less afraid of the lake?

Although life at the lighthouse isn't what Lucy hoped for, it is beautiful. Ships come and go, waves pound the rocks--and it has one major advantage: it's near the site of a famous shipwreck, a shipwreck that went down with a treasure her father wanted more than anything.

If Lucy can find that treasure--a priceless ruby necklace--won't it be like having Papa back again, just a little bit? But someone else is hunting for the treasure too. And as the lighthouse company becomes increasingly skeptical that the Martins can juggle Lucy and their duties, Lucy and the Martin children will need to find the necklace quickly--or they may not have a home at all.