The Nine Realms — Tony Bury

After their father's disappearance, Kayla and Dimitri were abruptly relocated to an enormous old house in the middle of nowhere. Bored and lonely with only their busy mum for company, the twins start to explore the seemingly endless rooms. Discovering a strange door in the floor of a darkened room which lay close to a curious Latin inscription etched into sandstone. Kayla and Dimitri are determined to solve the puzzle of the secret door. Kayla makes a breakthrough when she is guided to a hidden room by an unlikely friend and discovers a set of ancient maps and keys.Kayla and Dimitri solve the puzzle entering through the secret door in the floor and find themselves in a whole new world. But their fascination with being met by Sir Lancelot himself is soon tempered by the fear of what will now face them in the nine realms, and the threat to their family in a place populated by gods and goddesses, knights and wizards and every fabled creature they have ever read about. Kayla and Dimitri are about to have their strengths and weaknesses tested in ways that they could never have imagined...