Bad Seed

Bad Seed is the episode in which the series argues with itself about whether killers are made or born, and it stacks the argument in favour of the frightening answer. A series of vicious murders sends Bradfield reeling, and Hill becomes convinced they are the work of William MacAdam — known in the press as Mack the Knife — a killer newly released after serving a long sentence, during which he was educated. MacAdam is now a PhD student in Hill's university class and is conspicuously eager to become a media authority on serial killers.

The episode's opening establishes both halves of the plot. A prostitute named Anya and a young married couple called Johnson are found murdered, and suspicion falls on Dave Andrews, a butcher who had repeatedly quarrelled with the Johnsons as neighbours and who turns out to be a paedophile they may have discovered. Thompson then presents himself to Hill as an urgent suspect in the new murders too, because the signatures are closely similar. The show wants the audience to feel the pull of the obvious answer and the discomfort of liking it.

That discomfort is the point. A man who has paid his debt, been educated inside, reformed and now wants to work in the same field as the psychologist who helped convict him is a far more unsettling presence than a killer still at large, because there is no legitimate reason to exclude him. Daragh O'Malley plays him with a professional warmth that never quite settles into sincerity, and the performance is the best thing in the film.

Set against that is Jordan's wish to have a child before it is too late, which the episode ties directly to the case. Hermione Norris and Robson Green play the disagreement as one where Jordan is plainly right and Hill plainly evasive, and the show allows her the argument rather than arranging for him to win it. It is the most explicitly personal material in the Norris era, and it arrives in an episode with a high body count, which produces an odd tonal clash for the middle section.

That clash is the film's real weakness. Niall Leonard's script has two strong ideas — the reformed killer and the fertility theme — and it commits fully to neither, so the episode alternates between them rather than making them one thing. The plotting is also more tangled than the summaries suggest, with a paedophile suspect, a neighbour dispute, a name change and a media subplot all competing for the same hour.

The episode drew 7.40 million viewers. Its most useful contribution to the run is the interrogation of the series' own premise: if a killer can be reformed, then Hill's expertise is a life sentence rather than a diagnosis, and the show would pursue that thought much further in 2008 with the cannibal psychiatrist Michael. Bad Seed is where the question is first asked properly.