The player takes on the role of an unjustly executed man, who pleads to the devil to spare his life at the moment of his demise. The devil (explicitly referred to as 'Satan' in the manual) grants his request, and gives him command over the 'Castle of the Damned'. Soon after taking control of the castle, many visitors soon find themselves drawn to the fortess: some for power, some for salvation, and some for something as simple as shelter. The player has the option of either destroying the intruders or letting them escape, but both choices carry consequences. Source: Wikipedia, "Tecmo's Deception: Invitation to Darkness", available under the CC-BY-SA License.