Amaranthine

There was but one witness to the murder of Richard Mallory, which happened months ago. It was his adolescent son, Alfred, who saw it all happen. A stranger wearing a dark cloak was responsible. This he knows with all his heart, so he begins an investigation to do his late father justice.
At first, the whole affair is nothing more than smoke and mirrors. He is no closer to finding the culprit than anyone. Then, one day, he runs into the murderer himself. It sets off a chain of events that send Alfred to fight an ancient kinship shrouded in mystery which is much darker than what could ever be found at humanity's worst.
Realising that he cannot possibly bring down the murderer by himself, it is up to him to make connections that give him a fighting chance. Along the way, these new connections become close friends, but some of these friends have histories that are just as dark as the kinship. As it turns out, that darkness may be the key to bringing down the murderer, the kinship, and doing his father justice.