Hole in the Heart

Hole in the Heart opens with Hill talking a student down from a ledge and then losing him anyway. Kurt does not stay in therapy long enough to be helped; he disappears to join a new group of friends, and Hill is left feeling inadequate. It is a small failure and it is the right way to start an episode about a cult, because the episode's argument is that the people who are gathered by a charismatic leader are the ones everybody else has already stopped looking at.

The case itself arrives as a series of tableaux. A businessman and his accountant die in a fire that looks like arson, and there is no reason for the deaths that the investigation can find. Theirs are not the last pair of corpses found in Bradfield. The complexity of the scenes is what leads Hill to his deduction — that the corpses are neither both murder victims nor both willing suicides, but something more complicated — and the episode is unusual in making its progress through the visual arrangement of the dead rather than through testimony. Masonic symbolism sends the police to a local lodge and yields nothing, which is the show being honest about the cost of a false trail.

The realisation Hill arrives at is that the deaths correspond to the martyrdoms of Christian saints. Someone is breeding murderous martyrs, and the deaths will continue until the source is found. A local vicar with links to many of the perpetrators looks like the natural candidate, and when he kills himself in a straightforward suicide Hill understands that he was an ordinary member of the cult disposing of himself to protect the leader. Hill then builds Fielding a profile of the true leader from the ways the perpetrators were gathered.

That structure — a group of killers assembled by someone whose method is recruitment rather than murder — changes the detective problem in an interesting way. The profile has to identify the collector rather than the person holding the knife, and the show is better than usual at showing why that is harder: there is no single crime scene to read, only a pattern across scenes.

The episode's weakness is one the show periodically suffers from. The saint-death tableaux are the most striking visual design in the fourth series, and they are more memorable than the solution they point towards. The masonic thread consumes screen time and returns nothing, and the resolution arrives through Hill's synthesis rather than the investigation's work.

It drew 7.70 million viewers, one of the series' best. It is also the episode that introduces Ben Fielding, Alex's son, played here by Aaron Crisp, whose domestic presence the show would use as the source of Fielding's pressure throughout the fifth series. The film's quieter achievement is that its theme and its plot match: both are about people who are easier to recruit than to notice.