Black Butler, Vol. 2 by Yana Toboso

As high society's social calendar opens up and the Season draws to a close, London is gripped by fear. Someone has taken to stalking women of the night and painting the town red...in their blood. The name on everyone's lips seems to be "Jack the Ripper" - and as a result, the name on Queen Victoria's lips is Phantomhive. Summoned to London to clean up the mess created by this madman, Ciel Phantomhive arrives with Sebastian, his extraordinary butler, at his side to pour him tea, polish his silver, and...investigate a serial killer. And with the aid (and occasional interference) of a few of the Phantomhive house's numerous acquaintances, little stands in the way of the young earl getting to the bottom of this mystery. However, one question remains...can he handle the shattering truth behind it?