 The companions find themselves in Victorian London. Girls are being kidnapped off the street, ghosts have been sighted in the opera house run by Henry Jago, and giant rats haunt the London sewers. At the center of the chaos is a mysterious Oriental magician named Li H sen Chang. Chang serves a man he believes is the god Weng-Chiang, and is searching for a cabinet lost by his master. The Doctor uncovers the truth, however -- Weng-Chiang is actually Magnus Greel, a tyrant from the 60th century whose escape back through from that century have transformed him into a disfigured monster. (Originally broadcast in six parts.)