The Hidden Series by Lian Tanner

'Petrel leaned on the rail, watching the ice cave and stamping her feet for warmth. The berg came closer. That's when she saw him. Laid out on the ice like a dead fish, with a scattering of snow covering his face. A boy, where there should have been nothing but the memory of winter. A frozen boy.'Twelve-year-old Petrel is an outcast, the lowest of the low on the Oyster, an ancient icebreaker that has been following the same course for three hundred years... more'Petrel leaned on the rail, watching the ice cave and stamping her feet for warmth. The berg came closer. That's when she saw him. Laid out on the ice like a dead fish, with a scattering of snow covering his face. A boy, where there should have been nothing but the memory of winter. A frozen boy.'Twelve-year-old Petrel is an outcast, the lowest of the low on the Oyster, an ancient icebreaker that has been following the same course for three hundred years. In that time, the ship's crew has forgotten its original purpose and broken into three warring tribes. Everyone has a tribe except Petrel, whose parents committed such a terrible crime that they were thrown overboard, and their daughter ostracised.But Petrel is a survivor. She lives in the dark corners of the ship, speaking to no one except two large grey rats, Mister Smoke and Missus Slink. Then a boy is discovered, frozen on an iceberg, and Petrel saves him, hoping he'll be her friend. What she doesn't know is that for the last three hundred years, the Oyster has been guarding a secret. A secret that could change the world. A secret that the boy has been sent to destroy, along with the ship and everyone on it... less

Sharkey was born on a fortunate tide, and everyone on the giant submersible Rampart knows it. He's a hero, a future admiral, beloved by the ancestors. The trouble is, it's all based on a lie, and now Sharkey is thirteen, the whole thing has begun to fall apart. He's been a fake hero for years, but when tragedy strikes, he must become a real one. And he has no idea how to go about it.. moreSharkey was born on a fortunate tide, and everyone on the giant submersible Rampart knows it. He's a hero, a future admiral, beloved by the ancestors. The trouble is, it's all based on a lie, and now Sharkey is thirteen, the whole thing has begun to fall apart. He's been a fake hero for years, but when tragedy strikes, he must become a real one. And he has no idea how to go about it...Meanwhile above water, Petrel, Fin and the crew of the Oyster are on a mission, a mission to defeat the Devouts and bring knowledge back to the world, a mission they have no idea how to carry out. When the Captain of the Oyster comes up with a plan, Fin and Petrel have no choice but to accompany him - no matter how ridiculous or how dangerous the plan seems ...Can the Sunkers and the Ice Breakers put aside their differences and work together? Or will the Devouts finally catch up with them all? less

Gwin is a Fetcher. With her papa and twin brother, Nat, she travels West Norn, bringing joy to its downtrodden people through song and story. But ever since Mama died, it's been hard to keep the joy alive.Proud and defiant, Fetchers have always been hunted by the Devouts for preserving the old ways. So when devious Brother Poosk captures Papa, Gwin must rescue him—whatever the cost.Meanwhile, the Oyster's crew and the Sunkers lay siege to the Citadel... moreGwin is a Fetcher. With her papa and twin brother, Nat, she travels West Norn, bringing joy to its downtrodden people through song and story. But ever since Mama died, it's been hard to keep the joy alive.Proud and defiant, Fetchers have always been hunted by the Devouts for preserving the old ways. So when devious Brother Poosk captures Papa, Gwin must rescue him—whatever the cost.Meanwhile, the Oyster's crew and the Sunkers lay siege to the Citadel. But without their Sleeping Captain, can they ever win against the ruthless Devouts? Can Petrel, Fin, Sharkey, and Rain ever bring light back to such a dark world? less