Tinderbox used to be a quiet rural paradise until a spate of gruesome murders disturbed the local harmony. Having brought those guilty of the crimes to justice, the children of the Tinder Detective Agency discover that hell can come in many disguises and when you least expect it. When their cousin visits for Christmas, she brings with her a secret that even she doesn't know she possesses, and the agency's latest investigation takes a dark turn that leads them to the gates of hell itself.