Forbidden Sea Series by Sheila A. Nielson

A mermaid haunts Adrianne's dreams . . . is she coming to warn her, save her, or drag her down into the depths of the briny sea forever?When Adrianne comes face-to-face with the mermaid of Windwaithe Island, of whom she has heard terrible stories all her life, she is convinced the mermaid means to take her younger sister. Adrianne, fierce-willed and courageous, is determined to protect her sister from the mermaid, and her family from starvation... moreA mermaid haunts Adrianne's dreams . . . is she coming to warn her, save her, or drag her down into the depths of the briny sea forever?When Adrianne comes face-to-face with the mermaid of Windwaithe Island, of whom she has heard terrible stories all her life, she is convinced the mermaid means to take her younger sister. Adrianne, fierce-willed and courageous, is determined to protect her sister from the mermaid, and her family from starvation. However, the mermaid continues to haunt Adrianne in her dreams and with her song. less

When sixteen-year-old Sadelyn Hanson washes up on the shores of Windwaithe Island, her beauty and the strange marks on her wrist make superstitious locals suspect she is a mermaid. Feigning amnesia, Sade hides a far worse secret: she was sailing to her own murder trial when she was thrown overboard by the real killer, the cunning and cruel Captain Westwood.Sade's quiet effort to rebuild her life on the island is threatened when she meets an actual young merman... moreWhen sixteen-year-old Sadelyn Hanson washes up on the shores of Windwaithe Island, her beauty and the strange marks on her wrist make superstitious locals suspect she is a mermaid. Feigning amnesia, Sade hides a far worse secret: she was sailing to her own murder trial when she was thrown overboard by the real killer, the cunning and cruel Captain Westwood.Sade's quiet effort to rebuild her life on the island is threatened when she meets an actual young merman. Unable to speak his language, Sade still longs for the warm companionship he offers, despite the locals' dire legends about merfolk and their dark magic. But her confused feelings for the impossible boy become the least of her problems when Captain Westwood's ship docks at Windwaithe. With nowhere to escape, Sade must trust in the one person who doesn't fear the merfolk. A woman who had dealings with them herself—years ago. less