In 1879, a wealthy young woman elopes with an impoverished fisherman, leaving her family, who live on the volcanic island of Lanzarote, distraught. In 1968, 23-year-old Perdita West, secretary to the famous author Cora Gresham, visits Lanzarote, the strangest and most wild of the Canary Isles, on a research trip. They meet Cora's estranged son, Mike, and fall in love with the unusual, beautiful little island. While snorkeling, a landslide traps Perdita in an underwater cave. No one knows where she is, so she can't count on a rescue. And her efforts to save herself will reveal the solution to a century-old mystery.