Isaac Marcus Francis battles demons, monsters and more for a living with his loyal mutt Galiane. But when a horde of demons infests a small county in Europe he knows not all is as it seems. Soon Marcus finds himself facing notorious villains from history such as Dick Turpin and James "Killer’ Miller. Desperate for help against the impossible odds Marcus looks for the only people who would know how to defeat an immortal. Other immortals.

With the help of John Dee, Marcus races against time to stop the diabolical plot of the immortals before it is too late. Fighting demons, Hispanic bogeymen and more Marcus will stop at nothing to keep the world safe.