But when the theatre then plunges into darkness and you are greeted with the sound of retching, you are reminded that you are, in fact, about to be plunged back into the grimy streets of Irvine Welsh's Edinburgh.
It's unsettlingly familiar territory for Sage Theatre patrons, the same streets that were visited in the production of Welsh's Trainspotting four years earlier. I realized from my first exposure to Sage Theatre, to see Trainspotting, that this was a theatre company utterly unafraid to present controversial works. In the intervening years rarely have I been disappointed in the production choices and in the treatment of often inflammatory subject matter.
And it's hard to find a more inflammatory protagonist than Detective Sergeant Bruce Robertson of the Edinburgh Police Department. A corrupt, racist, misogynistic, often sadistic man, Robertson tells us that he was drawn to law enforcement because as a youth he had personally witnessed the power of the law and the brutality with which it was carried out, and he "wanted a part of it". He can have a certain charm to his swagger, an artfulness that comes with the confidence of knowing how to play the system. This charm wears thin as we come to realize the depth of Robertson's depravity, how very nihilistic he really is.
Frank Zotter plays Detective Robertson with a disturbing corporeality. He swaggers, he farts, he spews sausage roll crumbs. And he overshares as he complains of a testicular rash and anal itch, continuously scratching and tugging at the offending parts.
Filth is a very physical play, and since it is a one-person production, with Zotter tackling all 28 characters, it is highly demanding territory for an actor. Zotter very capably transforms from Robertson into the other characters with a change of voice, a shift in mannerism and facial expression, sometimes a simple adjustment of wardrobe. Throughout the two act play, Zotter is a force of nature, throwing himself into his characters, with an intensity that holds you in its thrall. Even Robertson's tape worm, which increasingly asserts itself as both a physical ailment and an internalization of moral corruption, is given a voice and an embodiment.
It's the tape worm who ultimately peels back Robertson's severely damaged scruples, revealing shocking truths about this unrepentant sociopath. And when the darkness ultimately falls upon stunned silence, we may not like Detective Sergeant Bruce Robertson, but we do pity his soul.