For most police officers, dealing with 'crackpots' is simply part of the job. The people who call up confessing to murders they couldn't have committed or which might never even have happened, the obsessives with nothing better to do than report non existent crimes or exaggerate run of the mill occurences into major events. As far as Tony is concerned Clark Dornan is one of these 'crackpots'.
For years Clark has been coming to the station with accusations against his neighbour, insisting that there is something horrible going on in the house across the road. When Clark eventually decides to investigate for himself and is reported missing a week later, Tony is forced to finally investigate Clark's outlandish claims, though once he arrives he realises that perhaps those claims were not outlandish enough.
'Behind Closed Doors' is a tale of investigation and terror, showing that sometimes when following the breadcrumb trail, there is something far worse than a house of gingerbread waiting at the end.