The first series of Luther scared the hell out of me on at least one occasion. I couldn't help but wonder: could it top that? Should it? Well, series two was certainly going to try.

While Alice Morgan (the devilishly delightful Ruth Wilson) sits in a mental hospital, DCI John Luther (Emmy nominee Idris Elba) makes a half-hearted attempt to kill himself. You can't blame him, considering that he lost his wife at the hands of his close friend last series. When that doesn't work, he turns to an awkward friendship with his wife's lover Mark North (Paul McGann) and of course, to his job. There's always somebody wandering down a side street, alone, in the middle of the night, after all. How many crimes would be avoided in television-land if people would stop doing that, I wonder?

Springing his partner Ripley (Warren Brown) from a boring new assignment, Luther joins up with DS Erin Gray (Nikki Amuka-Bird) under the authority of former adversary Warren Schenk (Dermot Crowley) to investigate the murder of a young woman by a guy in a Punch mask. She's only the first of his victims. Simultaneously, Caroline Jones (Kierston Wareing) turns up asking Luther to rescue her daughter from trouble. Just another messed-up, conflicted day at the office.

John Luther lives in a really screwed-up world, and he's suitably dysfunctional to go along with it. Rescuing Caroline's daughter Jenny (Aimee-Ffion Edwards), he's unafraid to literally carry her out over his shoulder. He's prone to doing questionable things, but we don't argue with him, because he's played by Idris Elba. Who wants to argue with a man that imposing? I'd be afraid that he'd just snap me into pieces. But by the same token, I don't think anyone else could play this role besides Elba. John Luther is larger than left, and so the man who plays him is as well, in every aspect. Elba is just as good now as he was before, as if he hasn't missed a beat in his performance.

So much of this first episode of Luther is devoted to catching the audience up on what has happened between the end of series one and now (in fact, the first words of this episode are the same as the last ones spoken at the end of last series), and introducing us to the new characters who'll play a part. That's to be expected and forgiveable, if a tad troubling as this series is only four episodes long, so there's not a lot of time for the show to tell its story.

By the conclusion of the episode, though, we're back to old times: ominous shots of dead bodies, oddly framed camera shots, creepy moments where the killer and Luther play a back-and-forth while we bite our nails. Based on this episode, series two seems less graphic than series one - fine by me, as series one was a little too graphic for my taste - but just as disturbing. Less is more, in that sense.

But despite that, there's that cliffhanger: still heart-stopping. I honestly jumped in my seat when I saw who the killer's next intended victim was. Wow.

There's a great scene at the episode's end between Luther and Schenk, where the latter tells the former how he had to fight to get him back on the force, and Luther admits that he's angry (at what? at losing another victim to the killer? at losing his wife? both? does it matter?). We know that he's always one step from having the wheels fall off, as Schenk puts it. Yet would we want anyone else chasing down these criminals? No, we don't. We'd probably be too scared to face them. Luther reminds us that as much as John Luther needs the job to stay sane, we need him to go to the places we'd never dare, and protect us from the things that come out of them.