When Nightmares Come is a tabletop miniatures wargame about modern day monster hunting and occult investigations. Players will form a team of paranormal vigilantes; self-taught occult specialists and monster hunters who call themselves the Nightwatch. These self-appointed members of the 'watch look to tackle the supernatural horrors and investigate the strange disturbances that plague their city.

The core of the game, using the Action Dice Pool with its multiple die types, is fast and bloody, with tiered enemies, flexible player classes, quick combat resolution, and straightforward mission objectives.

When Nightmares Come also contains a roleplaying element that allows for non-combat challenges and dramatic encounters. This system uses the same dice types as the core game's Action Dice Pool and emphasizes quick resolutions. This narrative system adds a fresh dimension to the core miniatures experience, particularly in longer campaigns where the promise of different foes and new storylines encourages long-term playability.