In the previous book, Robin Fellows was opened to a whole new world after his Gran died, a world of magic. After learning air magic, better known as the Tower of Air, from his teacher, who turned out to be his foe in disguise. Robin obtained the force of the Tower of Air itself, the Shard of Air. In this book, "The Drowned Tomb", written by James Fahy and published in August 18, 2016Robin gets a new mentor to continue in his magic studies. He starts learning the Tower of Water. The book is about Robin obtaining the Shard of Water. During one of his magic lessons, Robin discovers a tomb of an Undine, the masters of the Tower of Water, in which he finds a cylindrical puzzle, within which Robin believes is a scroll that may reveal the location of another shard. My favorite character in this book was Henry, because of his courage and the tricks he pulled. Without him, Robin would have never found the Shard of water. The book was very detailed, but still left enough room for imagination. Especially the tense scene when Robin and Henry got captured along with their escape was well written. One thing I found frustrating was that the Shard of water was broken in half, but in a way it makes the series more interesting.