David Williams has written a mystery, Murder in Advent, that features a chained library.[14] In the film Harry Potter and the Philosopher's Stone, the Restricted section of the library features chained books. In the season six finale of Game of Thrones, Samwell Tarly is granted access to the Citadel Library where many of the books are chained. In the film Doctor Strange, the library of Kamar-Taj is home to countless ancient books, but some books are forbidden and on chains and watched over by the librarian, Wong.[15] The Unseen University (UU) is a school of wizardry in Terry Pratchett's Discworld series of fantasy novels.