“Here we are again, happy as can be, all good pals and jolly good company.” So runs a cheery song from the 1930’s, which I remember learning on my grandmother’s knee; you’ll hear it - and a handful of other music-hall classics - at intervals during this offbeat and rewarding play. But the lyrics carry a heavy irony, for the warring couple at the heart of the script are anything but pals… and husband Andrew is far from happy, spiralling into a world of guilty fantasy and pitiful self-destruction.

Here We Are Again is the third part of a trilogy, devised and performed by locally-based Wired Theatre over the course of the last three Fringes. That long-running storyline is a remarkable achievement in itself - all the more so because while elements are very familiar from last time, there’s also a lot that’s changed. Once again, the play’s presented not on a stage, but in an ordinary house in Hove; once again, the action opens in the late-middle-aged Andrew’s study, before spreading out to other rooms. But while previously he introduced himself as a psychologist, now he explains he’s a cleaner - a sure sign that his life is on a downward trend.

Disconnection with reality is a hallmark of this play, and I often found myself wrong-footed by a scene which suddenly revealed itself to be something quite different from what it seemed. I’m still not absolutely sure whether certain details were for real, or a figment of Andrew’s disturbed imagination; the implications are dark either way. Yet there are moments of lucidity: the play starts with Andrew reading a “case study”, evidently a confessional for his own psychological flaws, and it ends with a gut-wrenching flash of self-realisation poignantly delivered by actor Robin Humphreys.

Compared to the preceding instalments, this production is surreal - at times even absurd - signalling and reflecting Andrew’s looming breakdown. There are incongruous songs and some free-association flights-of-fancy, many involving Andrew’s personal bête-noire Piotr, played with a delicatre mix of innocence and threat by Graham White. Some later scenes grow comically grotesque, but (for me, at least) avoid the trap of tipping over into overt black humour. They still serve to show us what Andrew is thinking, and that really isn’t funny at all.

If you did last year’s show, you’ll be in on a secret: one of the characters who appears in this instalment can’t, in reality, be there. There are clues that something’s awry, but they’re diluted by being mixed in among so much surreal weirdness, and if you don’t already know the back-story I suspect you’ll leave with quite a different view of the truth of what’s transpired. But does it matter? On reflection, I don’t think so. The two halves of the audience may hear slightly different stories, but they both make sense and they both lead to the same conclusion.

My one regret is that with so much dialogue centred on Andrew and Piotr, the two female characters don’t get much of a look-in; the ever-spellbinding Jackie Thomas deserves more time to develop her heart-rending story of abandonment and self-blame, while Andrew’s wife Sheila - played convincingly by Gillian Eddison - in this instalment is largely a foil for the two men. But overall this is a fitting end to Wired’s ambitious trilogy, which finds new angles on the now-familiar story and even new ways to use the unconventional performance space. Director Sylvia Vickers, and the whole cast and crew, have delivered the goods once again.