The nightwatchman is a well-timed five minutes late. A crowd has gathered in the square and is getting restless when he appears in a swirl of cloak and clank of halberd, as if sprung from a trapdoor. Tall and silent, he stomps through the tangle of intimidated tourists and onto the town hall's steps.
"Well? What are you waiting for? Who wants a selfie?" he shouts, breaking into a big grin under his black tricorn hat.
Hans Georg Baumgartner is a Pied Piper of history. Sometimes 300 people follow him on his nightwatchman tour through Rothenburg's streets. He's engaging and witty, with an off-beat edge to provide a frisson of unpredictability.
"The nightwatchman's duties were to keep lanterns lit, announce the hours, watch for fire, and protect citizens from thieves and cutthroats," he explains as we set off through dark streets.
"In the old days, I'd have been quite unsafe, but I don't feel so tonight as you'll all be following me!" he quips. "By the way, after hangmen and gravediggers, watchmen were the lowest profession. Good to know I'm better paid – thanks for coming!"
Baumgartner's comic timing is impeccable, his tone tongue-in-cheek. He doesn't take tourism's idealised past seriously, although that idealism is alive and popping with geraniums in Rothenburg-ob-der-Tauer, Germany's best-known old town. It seduces with cobbles and cuteness, presenting the Middle Ages as a merriment of cream pies and romantic wall-top walks.
The nightwatchman dismisses it all. "Imagine the filth in the streets from thousands of poultry, pigs and horses. People emptied their chamber pots outside, and the stench from the tannery must have been outstanding. The rats! The plague!"
He marches down the street, pointing out hooked beams under eaves, part of a pulley system once used to haul goods into attics. "As sieges were an ever-present threat, citizens were required by law to store enough grain to last the family an entire year."
The old days were dangerous. The city gates shut at night and everyone feared what was over the horizon. As we head onto the battlements – whose spectacular views of Rothenburg are a calendar classic – Hans explains how that fear came true in 1631 when the Lutheran city of 5500 found itself under siege from a Catholic army of 40,000.
A cannon shot hit the city's main gunpowder storage tower, blowing a hole in the defences. The town as sacked. Three years later, the plague returned.
"That was the end of Rothenburg's bad old days, and then they had 300 years of even badder old days, so little changed. It isn't romance but poverty and despair that give the town its look."
Onwards we go, around the walls and into horror tales, amusingly told, of boiling oil and betrayal, and then in 1945 of the Allied bombing that destroyed 300 buildings and a swathe of Rothenburg's famous walls.
"I know, you're thinking there must have been some positive aspects of history, and you're right," says Baumgartner. He pauses. 'But really, I can't think of any. There were no good old days."
Our final stop is an ancient pub called Zur Holl, or To Hell, under the sign of a golden devil, and one of Rothenburg's few late-night eateries. "It's not a bad place, so when someone tells you to go to hell in Rothenburg, it's a recommendation."
For most of the time Rothenburg really was hell, concludes the nightwatchman. Finally, the tourists came and changed its destiny, so there was a happy ending at last. "Now we're back, rich again and famous all over the world, and all because of you!" says Baumgartner, grinning and holding out his hat for tips.
Brian Johnston travelled as a guest of the German National Tourist Office, Romantic Road and Rothenburg-ob-der-Tauber.
Etihad flies to Abu Dhabi (14.5hr) and Frankfurt (7hr). Rothenburg is a two-hour drive from Frankfurt. Phone 1300 532 215, see etihad.com
The Romantic Road Express coach links Rothenburg and other towns on this tourist route, and connects to Frankfurt and Munich airports. See touring-travel.eu
The nightwatchman gives tours daily at 8pm between mid-March and Christmas. No reservations required. A donation is requested. See nightwatchman.de