Although his police salary wasn’t huge, he had hardly spent any of it for years, which meant that his account had swelled to such a size that a couple of months ago the bank had even sent him a card on his thirty-eighth birthday.

At that moment, however, with his finger on the bell to cabin 1211, he felt more like someone on the wrong side of fifty.

He pressed the polished brass button and heard a subtle chiming inside. The door was opened a few seconds later and he found himself facing a young man wearing a tailcoat, patent leather shoes and an obsequious smile. Martin recalled that the Sultan prided itself on providing a butler for every guest who booked an overpriced suite.

The specimen standing before him was in his early twenties, with short, black hair that, with its middle parting, stuck to his rather narrow skull as if ironed on. He had watery eyes and a receding chin. Courage and determination were not the first words that came to mind when looking at such an individual.

‘Show the gentleman in,’ Martin heard Gerlinde Dobkowitz call out from inside her suite. The butler stood to one side.

Martin’s brain had great difficulty in processing all the sights that assailed him once he entered.

As an investigator he knew that often you needed a very sharp pencil to draw the line between an eccentric lifestyle and madness requiring therapy. At first glance he could see that Gerlinde Dobkowitz straddled both sides of this line.

‘Finally!’ she greeted him from her bed. She was enthroned in a sea of pillows, newspapers and computer printouts. Her overladen bed stood in the middle of a space which the shipyard’s interior designers had originally specified as a living room. But they had not reckoned with Gerlinde Dobkowitz. At least Martin couldn’t imagine that flowery wallpaper the colour of raspberry mousse, a zebra fur rug or fake antlers above the air vents were part of the basic design of every three-room suite aboard the Sultan.

‘You need to recalibrate your tachometer,’ the old woman said, her eyes fixed on a wooden grandfather clock at the entrance to the suite. ‘It’s almost six o’clock!’

With a grumpy gesture she shooed her butler away to an antique, felt-covered bureau, which stood at right angles to the partition wall, beneath an oil painting that presumably once depicted Rembrandt’s Man with the Golden Helmet, but was now covered in notes attached to the canvas by drawing pins.

The old woman gave Martin the evil eye. ‘I thought I’d have to wait until New York to bring my brownies to the White House.’