The story of the film is set after the conflict instigated by Toyotomi Hideyoshi ended, but not before the Battle of Sekigahara determines who shall be the Shogun of Japan.

In Victorian-era Europe, a young boy loses everything he once held near and dear to a vicious plot. In his moment of death, he strikes a deal with a demon: his soul, in exchange for revenge. Ciel Phantomhive is now the head of the Phantomhive corporation, handling all business affairs as well as the underground work for the Queen of England. His new partner is a demon butler, Sebastian Michaelis, whose powers as a butler is only surpassed by his strength as a demon. The story follows the two along with their other servants, as they work to unravel the plot behind Ciel's parents' murder, and the horrendous tragedies that befell Ciel in the month directly after.

The story is set in Shanghai in 1931, when the Imperial Japanese Army has been dispatched to mainland China due to the relatively recent First Sino-Japanese War, Russo-Japanese War, and World War I. In this cosmopolitan city of intrigue, there is a special military spy organization called “Sakurai Kikan” that has since been buried in history.