Passed the Door of Darkness: Two young children dead, floating face down in their family's bathtub. Their mother, shot in the back of the head, lies next to the tub in a pool of her own blood. On the floor slumped against a blood covered wall is her husband, dead of a self-inflicted gunshot wound to the head. For rookie Homicide Detective Chris Malloy this grisly scene is more than he expected to see in his first week of working the graveyard shift. For his partner, grizzled yet poetic Detective Murphy MacCasey, this is but one tragedy among countless in his fifteen years in homicide. They haven't seen anything yet.