Warlord of Mars, Classics To Go

This novel continues where the previous one in the series, The Gods of Mars abruptly ended. At the end of the previous book, John Carter's wife, the princess Dejah Thoris, is imprisoned in the Temple of the Sun by the vile pretender goddess Issus. It is said one has to wait an entire Barsoomian year before the room the prisoner is in revolves back to the entrance. (Wikipedia)