Google ‘katoey’ and on the first page is a list of ten ways to spot one. It suggests that more than just a few clueless tourists pick up a beautiful girl on a night out in Thailand, to discover (or not) that she is, in fact, a he.

This is the fate of Jonno, the gullible Australian protagonist of Rob McBride's semi-fictional drama Katoey, showing this fortnight as part of the El Dorado fringe festival. “The first eight pages of the script,” explains McBride, over a late morning cup of coffee at the FCC, “are based on the experience of a guy I met here in Hong Kong. I heard his story and thought, what a great setting for a drama.”

Jonno (Will Haines), is on holiday in Phuket when he meets Sai (recent APA graduate Vincent Chiu), a transgender prostitute halfway through her sexual reassignment. Unaware that there’s anything unusual about her, Jonno brings Sai back to his hotel room where he finds, in the morning, that he has been robbed.

It is not until he arrives at the police station where Sai is being beaten for her petty crime that he finds out that she is, physically, male (“Vincent is willing to actually show us he’s male,” director Tom Hope says deliberately, revealing that the production will include scenes of full frontal male nudity). And off goes the action, hurtling in real time through the seedy sites of southern Thailand, through the lives, vendettas and ever more intertwined relationships of five troubled characters, as each confront, in one way or another, issues of sexuality.

“Sai is your classic [transgender] case of a woman trapped in a man’s body,” offers McBride, “So her sexuality is central to the play. She is dealing with the inner turmoil that such a discovery, and such a transformation, involves.” Jonno, too, is forced to question his sexuality as his friendship with Sai evolves. Throw in slimy Australian sex tourist Marty and a corrupt pedophilic cop or two, and the story gets messier. “More globally,” adds Hope, “The play is about love and power, and different manifestations [of both].”

McBride, an English journalist who has been based in Hong Kong for nearly two decades, wrote Katoey 11 years ago. Though there was a reading of it at last year’s Fringe Firsts, this is the first time the play has been staged (“It proved a bit difficult to cast,” the writer says sheepishly). As part of his research, McBride befriended a katoey working in Wan Chai’s red light district and, over a drink or two, found out her story while studying, as well, her mannerisms and idiom.

McBride hopes, before the play runs, to take his young male lead back to the sleazy streets of Wan Chai, to test whether Chiu is convincing enough as a woman. Having commandeered the talents of local drag queen and “makeup artiste extraordinaire” Teddy Lau Man-fai, the writer is happily confident this will work.

Katoey is likely to raise serious questions on sexuality and gender identity rarely dealt with on the city’s stages. As 22-year-old Chiu says, with surprising maturity, “I think it’s trying to capture Sai’s background that’s [the unique challenge of this role]. It’s not about the art of form here, it’s about understanding the physical and emotional things that have made this person’s childhood, her life, an ordeal.”

Katoey runs from Wednesday 10 to Saturday 13.