Indeed, the story of two sisters caring for an elderly mother who thinks she's a dog was never going to be an easy sell; but strong writing, fine performances and an intriguing new venue make Hot Dog more of a winner than a wiener.

Hot Dog, with its surreal premise, suburban American setting and slick 90-minute running time (no interval) is the sort of thing I'd normally expect to see programmed at the Donmar, Soho or possibly even Royal Court. Given the slightly ramshackle, speakeasy nature of the venue – The Last Refuge is essentially a large shed down a dodgy alley opposite Peckham Rye station – it's a pleasant surprise to find such high production values and an entertaining piece of theatre inside.

The premise is this: Maryanne (Penny Lisle) is a fortysomething woman who's cared for her ageing mother ("The Dog" – Tessa Hatts) for years – but both Mary and husband Michael (Ryan Anthony-Jones) want to move away to jobs and pastures new. Enter sister Carol (Rebecca Crankshaw), single, drifting, and in need of the money the Dog will pay to be looked after. The problem is that Mom is, quite literally, an old bitch; prone to emotional manipulation and verbal and physical abuse of both her well-meaning daughters. What to do with a dog who's had her day?

Descent Theatre has previously only produced short plays; Hot Dog is their first full-length show, and on such evidence, this fledgling company's commitment and professionalism is as laudable as their taste in new writing. The four actors are immaculately cast by director Faye Merralls, who also handles the drama with confidence, pace and wit: it's rare to find such a strong show so far out on the fringe.

Emma Bailey's detailed kitchen-sink set brings Middle America to South London, with the "floorplan" design a cheekily apt nod to Lars von Trier's Dogville, and even the chill of the unheated venue is thoughtfully combated by blankets and hot-water bottles for the audience. Overall, Hot Dog is a theatrical experience far superior to most you'll find even in well-funded (and heated) central venues.

There are niggles, of course, but very few; Anthony-Jones's American accent is not quite as flawless as everyone else's, and all of the actors are sometimes guilty of forgetting where the "walls" of the set are; but a superb ensemble performance led by the undoubted star of the show, the brilliantly loathsome Tessa Hatts, sweeps all before it. Hatts barks, bitches and snipes her way through all of the best lines with brio and relish, which perhaps explains why author Kosar chooses not to make the mother more doglike: this magnificent curmudgeon is too good a character to silence.

The dog idea is an interesting way of examining the emotional toll taken on adult children caring for demanding elderly parents, and to an extent it works; yet the fuzzy and shifting boundaries of the mother's dogness also expose a weakness in the basic concept of the play. For if being a dog is a pathological delusion on Mom's part it should be consistent; and if she's just f**king with her kids, well, doesn't she deserve what's coming to her? (Hint: it's not a juicy bone).

In the end, enjoyable though Hatts's delinquent performance is, what pathos and complexity does eventually emerge from Hot Dog comes too little, too late, and I couldn't help but feel I should have been more moved – or at the very least more disturbed – by the denouement. But the ambition of this piece, the talent of the author, and the high quality of the production are all beyond doubt, and when the dark laughs come thick and fast as promised, only a dog in the manger would give it less than four stars.

Hot Dog, at The Last RefugeKaty Darby reviews Hot Dog at the Last Refuge.4