Whatever else is going right or wrong with a TV show, it helps if we know immediately which series we’re watching. A shimmering brutalist landscape, “Russia” written in giant pastel letters, retro-reverb beehive pop on the soundtrack and a woman in biking leathers breaking into a government building wielding a gun and silencer? This can only be Killing Eve. This is season four. If you didn’t catch seasons one to three, what have you missed? Well, there’s a diffident but determined intelligence agent called Eve and a fearsome yet brittle assassin called Villanelle and they’re obsessed with each other because … actually we’ve never fully established why. Anyway, since Eve began tracking Villanelle, what has happened is … do you know, I’m not properly across that either? A criminal network called the Twelve keeps murdering beloved minor characters and Eve plans to destroy it, but what the Twelve wants or why we might care has remained murky. Killing Eve is funny, sexy and the source of numerous already brilliant actors’ best work, but it has made no sense for some time. When Phoebe Waller-Bridge originally dramatised the Codename Villanelle novellas by Luke Jennings, she filled the first season with one-liners so mischievous, an aesthetic so enviable and a main antagonist so exciting that television drama has rarely created such an overwhelmingly attractive first impression. Nothing before or since has felt as icily fresh as Villanelle, modelling vicious couture in a series of prime continental locations, dispatching victims with imperious calm. The problem was that Villanelle only worked as a mood, a vibe, a mythical beast. When season one climaxed with Eve – the MI5 desk jockey whose pursuit of the psychopathic Villanelle had awakened the carefree hedonist buried deep within her – stabbing her quarry in an outpouring of vengeance and lust, the only viable ending had been used up, but the show had become so intoxicating, it was bound to unwisely continue. But, not unlike Villanelle breezing out of a penthouse suite leaving bloody chaos behind her, Waller-Bridge sauntered off to work on other projects. Since then, Killing Eve has been a fiery training ground for female writers, with each season asking a new showrunner to attempt the impossible task of keeping the story going. Season four boss Laura Neal has the hardest challenge of all, not just because of Killing Eve’s generally diminishing returns – by this point we’re peering at a photocopy of a photocopy of a photocopy – but because this is the final season. A hint of where Neal is taking us comes in that first scene of the new run, when the armed biker we assumed was Villanelle removes her helmet to reveal that she is, in fact, Eve. Now free of the frustrating job and boring husband that used to tie her down by giving her something to live for, she is close to embodying the dark fantasy she used to covet from afar. She’s living in a hotel and enjoying a casual thing with a muscly colleague at the private security firm where she now works: he buys her burgers, sharpens her hand-to-hand combat skills, and cheerfully agrees to unfussy sex in a surveillance van, after a conversation about firing a weapon turns her on. Sandra Oh remains fantastic as Eve, whose gradual journey from nerdy safety to delicious self-destruction has been the only thing about the post-Waller-Bridge years that has ever really worked. Comer, on the other hand, is struggling as Villanelle, lost in the nonsensical idea of this stone-cold monster trying to find redemption. Season four reinvents her as working in a church, lodging in the vestry and undergoing baptism as part of her latest scheme to convince Eve, for reasons unclear, that she’s no longer evil. Mild carnage ensues, but her co-opting of Christianity is, compared to Villanelle at her awesome best, cheap and easy iconoclasm. The dull British setting prevents Comer from wearing any fabulous outfits, which, in a show that once unashamedly prized being beautiful on the surface, is another pleasure lost. The end of episode one hints at a solution to these issues that would certainly be ambitious, but looks more likely to come off as desperate. Before that, one of the series’ recurring motifs pops up yet again, when Eve and Villanelle share a confrontation that is not allowed to resolve anything: this time they are on either side of a fish tank, with Comer all in white. While the children of the 90s who make up the bulk of the audience might chuckle at the homage to Baz Luhrmann’s Romeo + Juliet, that sort of direct reference feels like something that the show in its pomp wouldn’t have resorted to. It’s still recognisably Killing Eve and it’s still kinda cool, but it’s out of new ideas.