6 books in series

The Children of the Red King

The Children of the Red King is a 6-book series with 6 primary works first released in 2002 with contributions by Jenny Nimmo.

Midnight for Charlie Bone
Charlie Bone and the Time Twister
Charlie Bone and the Invisible Boy
Charlie Bone und das Schloss der tausend Spiegel
Charlie Bone and the Hidden King
Charlie Bone and the Red Knight