Adopted as babies by two different families, Simone and Hannah have never known they are identical tRead Review
The Tide Knot
Sapphire and her brother Conor can't forget their adventures in Ingo, the mysterious world beneath the sea. They long to see their Mer friends once more. But a crisis is brewing far below the ocean's surface, where Saldowr, the wisest of the Mer, guards the Tide Knot. And soon both Sapphire and Conor will be drawn into Ingo's troubled waters.
I love this book so much. It lets on a whole new twist to your understanding of the ocean. How could two worlds ever do this, is a wonder I want to know. You need to start from the beginning to fully understand it but still all the same, it's my favourite in the series.