The theatre in the basement of Sydney’s The Old Fitz is tiny. It sits about 50 people; I have been in showers with a larger footprint than its stage. I say this not to be disparaging, but to underline how extraordinary it was to walk into the venue to see a platform built above the stage, ten musicians above and another five below. There’s not enough headroom for the players up the top to stand up, but there they are.

<i>The Seven Deadly Sins & Mahagonny Songspiel</i> at The Old Fitz, presented by Red Line Productions. Photo © Robert Catto.

The Seven Deadly Sins & Mahagonny Songspiel at The Old Fitz, presented by Red Line Productions. Photo © Robert Catto.

They are there to perform The Seven Deadly Sins and Mahagonny Songspiel, two separate but thematically linked works with music by Kurt Weill and text by Bertolt Brecht, best known for their The Threepenny Opera. All three works are irrevocably shaped by the cultural, musical and moral morass that was 1920s Germany, their worlds populated...