LUTHER, 2.3: the diceman cometh

The final two-part story began on a riveting note, with an attack on a petrol station's forecourt by a fair-haired weirdo (Steven Robertson), brandishing a bat and acid-filled water pistol, as the frightened customers watched from inside the adjoining shop. It was easily the show's most tense and gripping sequence yet, putting viewers immediately on the edge of their seats as the creepy stranger smashed windows and sprayed graffiti on a car roof, before clubbing one man to death on the ground. Indeed, this episode's highlights are the moments of violence and intimidation, when this week's villain reappears to chill the blood: shamelessly shoplifting from a small shop, jumping all over parked cars, or (in another bravura sequence) posing as a motorcycle courier to access an office building and indiscriminately bludgeon employees with a hammer.

It's a shame the actual storyline was even thinner than usual for Luther, as the investigation into catching this violent menace was almost comically sketchy. Luther concludes the man's using role-playing dice to determine his actions as a guess based on his hunched posture on CCTV footage, and the police essentially caught their man by waiting for the day's most bizarre crime-in-progress and blindly hoping the perpetrator's the man they're after. I don't expect intricate, watertight plotting on Luther, but the way the story unfolded was rather imprecise, even for this show.

As usual, a lot of slack was taken up with a subplot involving Jenny (Aimee-Ffion Edwards), as Luther was forced to steal confidential police data and deliver it to Toby (David Dawson) to keep her safe, which aroused the suspicions of DS Gray (Nikki Amuka-Bird) after she saw Luther sneaking around the offices during a fire alarm she reasons he triggered to empty the building of prying eyes. I'm still not wholly convinced by this storyline, as the show's done a poor job explaining it (perhaps because it's had to cut corners because there are only four episodes?), but the situation with Gray beginning to suspect Luther of something criminal is an interesting one. Unlike in series 1, when Luther was framed for a criminal act (killing his wife), this time he's genuinely at fault—even if his actions are understandable because he's trying to protect someone he cares about.

Episode 3 was chock-full of intense moments that played to Luther's strength as a larger-than-life cop thriller, and that alone nudged this episode's rating up by a half-star. It also offered a great setup for the finale, with Jenny having killed the amoral Toby in self-defense when he attempted to rape her (will Luther dispose of his body?), and the twist that the madman has an identical twin and partner-in-crime was exactly the kind of oddness this show delivers so efficiently. It walks a fine line between brilliance and preposterousness, but for the most part Luther gets the balance right. It's just a shame series 2's a mere four hours long, with only enough time to tell two stories, as some of the subplots could have done with more time to develop.

Asides

• This was the first episode of series 2 that didn't feature Paul McGann or Ruth Wilson. In the former's case, it appears to prove the character of Mark North wasn't actually deserving of a return this year. Even his role as Jenny's "babysitter" didn't last long! In the latter's case, I'm surprised Alice hasn't been anywhere near as involved in the show as before. Hopefully she'll return for the finale to help Luther with the mess he's found himself in, but if Luther returns for a third series writer Neil Cross will have to come up with a good reason to keep her around. Alice is a terrific character, but at the moment it feels like she was brought back because she was popular and fun to write for, and not because there was a story worth telling.
• Pam Ferris had better return next week, too—because casting Miss Trunchbull as an underground porn baroness demands more than one short appearance over four episodes.
• Did you notice the nudge in the ribs about comics (or "graphic novels", according to Jenny)? A sly reminder that Luther is effectively a live-action comic-book, which some people don't seem to grasp.

written by Neil Cross / directed by Sam Miller / 28 June 2011 / BBC One