Trout Stanley, Southwark Playhouse

Award-winning Toronto-born playwright Claudia Dey is also an advice columnist and here she presents us with three wildly off-the-wall case studies. The twin Ducharme sisters, who share an isolated house in Tumbler Ridge, British Columbia, are famous for having a shared life marked by tragedy: their triplet died in the birth canal, their mother succumbed to a fever on their twentieth birthday and their father was split in two by lightning on the same day.

Grace, who works in a garbage dump, is outgoing and enjoys posing for the local catalogues and billboards, while Sugar is mousier, hasn't left the house for a decade and dances alone, dressed in her mother's garish, unwashed tracksuit, while dreaming of being rescued by a handsome doctor.

Dey uses the well-worn ploy of a stranger who enters and changes everyone's lives, except that an emotional explosion of some sort seems to have been on the cards here anyway. Trout Stanley, for it is he, shares some of the sisters' malfunction. He too is an orphan who, incidentally, killed a couple of cops as a teenager and also happens to believe his unborn twin is trapped in his chest. He drops in while on a mission, a long, slow walk to visit his parents' graves where they were electrocuted while employing a metal detector on a lake. All of which indicates Dey's enjoyment of tragedy tinged with absurd comedy.

Is Trout what he claims to be? His first visit is a clandestine one, at dead of night, during which he shows an intense interest in Sugar's grubby slippers. As it happens, a killer may be on the loose: a Scrabble champ-cum-stripper has gone missing in her sparkly costume.

This is the twins' thirtieth birthday and it should be a marker, the end of their misfortune. Trout - his parents died before he could ask why they gave him a fish for a name - falls instantly in love with Sugar. Grace has marked every birthday since the death of the twins' parents, the "Holies", by discovering a dead body. Will it be the same this year? Is she telling the truth? Could she cope with Sugar finding happiness and leaving home? A shotgun is introduced. The cliché has it that if a gun appears on stage, it will be used. Dey has her own way of dealing with that one, too.

There is never a dull moment. Rambling autobiographical monologues are intercut with dialogue which often has a poetic weave, down-to-earth but with startling images. There are fights and attempts at seduction, and relationships shift as the three gradually make their own peace. Grace claims, not very convincingly, that her billboard pose in shorts and cowboy boots, gun at the ready, is ironic. But irony exists throughout: a threat may have a benign outcome and vice versa. And always there is one certainty, that no-one can ever be certain of the truth, either past or present.

Matt Steinberg directs with style and energy, keeping a necessary rat-a-tat pace. The cast - Sinéad Matthews as Sugar, Vinette Robinson as Grace (pictured above, foreground) and Dylan Smith as Trout - are first-rate, inhabiting this weird world as if they belonged there.