Twelve-year-old Kela is still mourning her mother when she finds a mermaid's comb while she and her friend are looking for sea glass on her Caribbean island; such combs have magic in them, and touching it opens a connection to the mermaid Ophidia who can grant her wish, to bring her mother back to life -- but all wishes have consequences, and magic demands a price which may prove to be more painful than the loss of her mother.