The year is 1892. The Legion have unleashed an ancient darkness on London, leaving crime and chaos in its wake. From their rooftop base, The Watchers fight to restore order - looking to Ben Kingdom for hope. But unbeknown to them, Ben is harbouring a deadly secret that could put them all in danger.
As the Legion gather their forces for invasion, all they need for victory is the final Coin of blood. Ben knows that he could put an end to this battle, but on the darkest night of all - the Feast of Ravens - Ben's secret could destroy everything.