Ingo
Helen Dunmore
 In a flashback, Sapphire (Sapphy) remembers her father, Mathew Trewhella, showing her the carved Zennor mermaid who was slashed with a knife a long time ago by an angry human. She had been in love with a human man who eventually swam away with her and became Mer. By an apparent coincidence the truant man has exactly the same name as Sapphy's father. He is apparently her ancestor. Sapphy is haunted by her father's disappearance because he does not come back from the cove after an argument with her mother. Many people say he ran away with another woman, or has died, but Sapphy and her brother, Conor, who is two years older than she is, refuse to give up hope and secretly promise to never stop looking for him. About a year later Conor also disappears. Fearing that the same thing that happened to her father has happened to Conor, Sapphy sets out to look for him. She finds him speaking to a mysterious girl in the water at the nearby cove, and waits until the girl suddenly disappears. When asked about the girl, Conor behaves as if she were never there, and is shocked (and at first doesn't believe) that hours have passed since he went for a "quick" swim. The next day, Conor leaves again for the cove after their mother has left for work. Searching for him at the cove, Sapphy hears a beautiful voice singing a familiar song that her father had sung to her in the past. She calls out for her father and the singing stops. Suddenly she notices a boy perched on a rock. At first she thinks he is wearing a wetsuit pulled down to the waist but later realises that he actually has a seal's tail instead of legs. She nearly falls into the sea but the Mer boy, named Faro helps her keep her balance. When she calls him a "mermaid", he gets very scornful of humans, saying that him being a mermaid is "anatomically impossible" as he is, firstly, male and secondly, "all that scaly-tails and hair-combing mermaid and merboy and merman stuff comes from humans". He takes her through the Skin (the surface) and into the world of Ingo which is extremely painful at the beginning for a human, and you have to forget about Air to be able to survive. She also finds out that it works the other way for the Mer: it hurts them when they go into the Air, and if they stay to long, they will die. After an amazing time, Sapphy leaves Ingo only to realize that she has been there all day long instead of a few hours. As time goes by, Sapphy is affected more and more by Ingo, craving salt and the call of the sea. Ingo calls to Sapphire more strongly than it does to Conor. Her brother, worried Sapphire will "disappear," takes her to the wise Granny Carne, who imparts her knowledge about Sapphire and Connor's Mer inheritance. Granny Carne has earth power and can communicate with owls and bees, maybe even other animals. Roger, a diver and a new boyfriend of Sapphire's mother, plans to go diving near the Bawns. Sapphire learns that this is where the Mer go to die and Ingo is deeply hostile to anyone who goes there and that all of Ingo is prepared to defend what is held there. She also remembers that her father told her and Conor to never ever go near them and that it was dangerous. Sappy and Conor do their best to save Roger and his diving buddy Gray from the fierce seal guardians that protect that area. Conor is able to hear the seals song that they sing to the dying Mer, so he sings their song and makes them calm down. At first Faro and Elvira do not help, but then realize how brave Sapphire and Conor are so they help them. Sapphire and Conor, with Faro and Elvira's help, they get Roger and Gray back into the boat and cover them with foil blankets. Then when that night, as Roger is sleeping on the couch, he wakes up screaming from a nightmare and tells Sapphires mother that he was being thrown by underwater bulls. At this, Sapphire realizes that the memory of the incident still resides in Roger's mind, just below the surface.