A man is found poisoned at the foot of Cleopatra's Needle on London's Embankment, apparently having taken his own life. His identity is a mystery that Octavius Rixton (alias Octavius Fanks, detective) is determined to solve. A mysterious cryptogram leads Fanks to believe that oriental antiquities may provide the clue to the dead man's story. But what is the mystery of the Chinese Jar?