Mike Sullivan is a rookie cop in late nineteenth-century Los Angeles. There are only seventy officers on the squad, and they still ride horses on patrol. The city population reaches over one million, and crime increases with the growth; but Mike is a cop, ready to face any foe. Or so he believes.
When the Adelaide docks at San Pedro and off-loads two bodies that weren't on the manifest the L.A. force is placed on alert. An old sailor tells Mike that the deaths were the work of a vampire who rounded the horn on this last voyage of the season. Mike is skeptical until the sailor pulls out a copy of Bram Stoker's Dracula and suggests that Mike might find answers in there.
As Mike delves deeper into the mystery he is distracted: by his mother's serious illness and his love for Jennifer Fitzgerald, the woman he hopes to marry. But he must set all this aside. Having finished the book, Mike realizes that the old sailor is right: a vampire hunts the streets of Los Angeles. Conventional police work and his skill with his firearms will no longer be enough. But what will it take to get his fellow officers to believe and how will Mike protect those he loves from the horrors of night when L. A. Screams?