When she incurs Neptune's wrath by finding a diamond ring buried under rocks in the ocean, Emily is put under a curse that will force her to choose to be either a mermaid or a human and split up her parents forever.

Working as a youth minister after the tragic death of his fiancee, a man raised in foster care teams up with a spunky church custodian with her own unhappy past, before the pair find unexpected love and healing together.

Using the clues found in Aurora Beatrix Lane's travel diary, the Thea Sisters continue their search for the seven lost treasures; and the object this time is the Ring of Eternal Love, a journey that begins in Verona, Italy, with the story of Romeo and Juliet and takes them around the world.